Chemical Experiment and Application

Question 1

Question 1: 1. Ancient Chinese culture contains a wealth of chemical knowledge, the following statement is false...

1. Ancient Chinese culture contains a wealth of chemical knowledge, the following statement is false Country. "Alcohol from grain fermentation is dispersed in the lees and can be separated from the lees by distillation

A. A. Song - Wang Ximeng "thousands of miles of rivers and mountains," the paper used for the Xuan paper, the main component of a natural organic polymer
B. B. The main components of both green and gray hair in "The mirror in the high hall is sad about the gray hair, and the green silk is like green silk in the morning, and the gray hair becomes snow in the evening" belong to proteins.
C. C. The "Rough Talk of Things" records: "When the tomatoes are picked before they are ripe, three papayas are put into each basket, and when they get gas, they will be released and have no astringent taste", in which "gas" can undergo an agglomeration reaction, and the products can discolor the acidic $\mathrm { KMnO } _ { 4 }$ solution.
D. D. "Walking Among Guests": "The wine of Lanling is fragrant with tulip, the jade bowl is filled with amber light, but the host can intoxicate the guest, and I don't know where he is".

Answer

Answer: C

Solution: A. The main component of rice paper is cellulose, a natural organic polymer, A correct; B. The main component of green and white hair are keratin, belonging to the protein, B correct; C. "Gas" refers to ethylene, ethylene polymerization reaction can occur to generate polyethylene, but polyethylene structure is stable, can not make acidic. The $\mathrm { KMnO } _ { 4 }$ solution fades; and ethylene itself can make acidic $\mathrm { KMnO } _ { 4 }$ fade, but the title describes the nature of the polymerization product, so C is wrong; D. The separation of alcohol from lees utilizes the difference in boiling points, which can be achieved by distillation, D is correct.

Question 2

Question 2: 2. In order to remove impurities in the substance, the correct reagent for removing impurities is |...

2. In order to remove impurities in the substance, the correct reagent for removing impurities is | Options | Substance (impurity) | Removal reagent | | :--- | :--- | :--- | | A | $\mathrm { Fe } _ { 2 } \left( \mathrm { SO } _ { 4 } \right) _ { 3 }$ solution ($\mathrm { FeSO } _ { 4 }$ ) | suitable amount of chlorine water | B | $\mathrm { NaHCO } _ { 3 }$ solution ( $\mathrm { Na } _ { 2 } \mathrm { CO } _ { 3 }$) | suitable $\mathrm { Ca } ( \mathrm { OH } ) _ { 2 }$ solution | $\mathrm { Ca } ( \mathrm { OH } ) _ { 2 }$ solution | $\mathrm { NaNO } _ { 3 }$ | $\mathrm { Na } _ { 2 } \mathrm { SO } _ { 4 }$ solution C | $\mathrm { NaNO } _ { 3 }$ Solution ($\mathrm { Na } _ { 2 } \mathrm { SO } _ { 4 }$) | Appropriate amount of $\mathrm { Ba } \left( \mathrm { NO } _ { 3 } \right) _ { 2 }$ Solution | $\mathrm { NaNO } _ { 3 }$ Solution | $\mathrm { Na } _ { 2 } \mathrm { SO } _ { 4 }$ | Appropriate amount of $\mathrm { Ba } \left( \mathrm { NO } _ { 3 } \right) _ { 2 }$ Solution | D | $\mathrm { CO } _ { 2 } ( \mathrm { HCl } )$ | Saturated NaOH solution |

A. A. A
B. B. B
C. C. C
D. D. D

Answer

Answer: C

Solution: A. Chlorine water can oxidize ferrous sulfate to produce iron ions, but chlorine gas will be converted to chloride ions, the introduction of new impurities, does not meet the conditions of decontamination, A error ; B. The appropriate amount of $\mathrm { Ca } ( \mathrm { OH } ) _ { 2 }$ will react with $\mathrm { Na } _ { 2 } \mathrm { CO } _ { 3 }$ to produce calcium carbonate precipitate and sodium hydroxide, the introduction of sodium hydroxide impurity in the solution, does not comply with the principle of decontamination, B error; C. Appropriate amount of $\mathrm { Ba } \left( \mathrm { NO } _ { 3 } \right) _ { 2 }$ reacts with $\mathrm { Na } _ { 2 } \mathrm { SO } _ { 4 }$ to produce barium sulfate precipitate and sodium nitrate, and then filtering to achieve the purpose of impurity removal, C is correct; D. Saturated sodium hydroxide can react with both HCl and carbon dioxide, so it can not achieve the purpose of removing impurities, D is wrong;

Question 3

Question 3: 3. Laboratory for the following experiments, must not need to use the "zeolite" are

3. Laboratory for the following experiments, must not need to use the "zeolite" are

A. A. Preparation of distilled water
B. B. Fractionated oil
C. C. Preparation of ethylene
D. D. Hydrolysis of ethyl bromide

Answer

Answer: D

Solution: A. When making distilled water, zeolite is added to prevent boiling, so A is not chosen; B. Fractionation of petroleum is accomplished by distillation, and zeolites are added to prevent boiling of the liquid mixture, so B is not chosen; C. To produce ethylene, the mixed liquid needs to be heated to $170 ^ { \circ } \mathrm { C }$, and in order to prevent the mixed liquid from boiling, zeolite is needed, so C is not chosen; D. The hydrolysis temperature of ethylene bromide is low, so zeolite is not needed, so D is chosen;

Question 4

Question 4: 4. Chemistry is closely related to production and life. The following statements are not correct

4. Chemistry is closely related to production and life. The following statements are not correct

A. A. Flour mills should be labeled with the words or icons "no fireworks".
B. B. Ammonium chloride solution is commonly used to treat the weld prior to welding the metal.
C. C. Removal of suspended solids from domestic water using lead acetate as a flocculant
D. D. Washing clothes in hard water wastes soap and doesn't clean the clothes.

Answer

Answer: C

Solution: A. Flour mills often have combustible particles mixed in the air and limited space, which can easily lead to explosions in case of open flames, so flour mills should be labeled with the words or icons of "No Smoking or Fire", and item A is correct; B. Ammonium chloride solution is acidic, can eliminate the welding surface rust, B is correct; C. Lead is a heavy metal element, can not use lead acetate as a flocculant to remove suspended solids in domestic water, C error; D. Hard water contains calcium ions and magnesium ions, can be reacted with soapy water, generating insoluble precipitate, D correct; answer C.

Question 5

Question 5: 5. The following illustration shows a distillation apparatus.

5. The following illustration shows a distillation apparatus.

A. A. ![](/images/questions/chem-experiment/image-001.jpg)
B. B. ![](/images/questions/chem-experiment/image-002.jpg)
C. C. ![](/images/questions/chem-experiment/image-003.jpg)
D. D. ![](/images/questions/chem-experiment/image-004.jpg)

Answer

Answer: D

Solution: A. The device is an evaporative crystallization device, and A does not fit the question; $B$. B. The device is a dispensing device; B does not meet the meaning of the question; C. The device is a filtration device, C does not meet the meaning of the question; D. the device is a distillation device, D meets the meaning of the question; In summary the answer is D.

Question 6

Question 6: 7. Vehicles transporting sulphuric acid are marked with the chemical symbol ( ).

7. Vehicles transporting sulphuric acid are marked with the chemical symbol ( ).

A. A. ![](/images/questions/chem-experiment/image-005.jpg)
B. B. ![](/images/questions/chem-experiment/image-006.jpg)
C. C. ![](/images/questions/chem-experiment/image-007.jpg)
D. D. ![](/images/questions/chem-experiment/image-008.jpg)

Answer

Answer: C

Solution: Test Question Analysis: Sulfuric acid is corrosive, so the labeling of corrosion, so option C is correct. Exam point: the knowledge of chemical labeling.

Question 7

Question 7: 10. The Compendium of Materia Medica recorded: "They pick the genus Artemisia Polygonum, open the ce...

10. The Compendium of Materia Medica recorded: "They pick the genus Artemisia Polygonum, open the cellar to soak in water, liquefy, dry and burn ash. To the original water dripping juice, every hundred pounds into two or three pounds of flour. For a long time, the precipitate like stone. "In the laboratory to complete the operation, did not use the instrument is ( )

A. A. ![](/images/questions/chem-experiment/image-009.jpg)
B. B. ![](/images/questions/chem-experiment/image-010.jpg)
C. C. ![](/images/questions/chem-experiment/image-011.jpg)
D. D. ![](/images/questions/chem-experiment/image-012.jpg)

Answer

Answer: D

Question 8

Question 8: 11. The preparation of the following substances involves redox reactions

11. The preparation of the following substances involves redox reactions

A. A. Extraction of bromine monomer from bromine water by carbon tetrachloride
B. B. Oxygen preparation by separation after compressed air
C. C. Preparation of aviation diesel by atmospheric fractional distillation of petroleum
D. D. Preparation of silver monomers by heating silver oxide

Answer

Answer: D

Solution: A. Extraction is a physical change, no redox reaction occurs, A does not satisfy the question; B. compressed air after the separation of the preparation of oxygen as a physical change, there is no redox reaction, B does not meet the question; C. Atmospheric pressure fractionation is a physical change, no redox reaction, C does not meet the question; D. Heating silver oxide preparation of silver, silver from + 1 valence reduced to 0 valence, there is a change in the elemental valence, redox reactions, D to meet the meaning of the question. D. The answer is D.

Question 9

Question 9: 12. A reagent bottle labeled with the safety symbol shown in the figure, the reagent may be

12. A reagent bottle labeled with the safety symbol shown in the figure, the reagent may be

A. A. ethanol
B. B. caustic soda
C. C. potassium nitrate
D. D. alum

Answer

Answer: C

Solution: A. Ethanol is a flammable liquid and is not usually used as an oxidizing agent; B. Caustic soda is a strong alkali, belonging to the corrosive reagents, usually not used as an oxidizing agent, B does not meet the meaning of the question; C. Potassium nitrate can show strong oxidizing property under certain conditions and can be used as an oxidizing agent; D. Alum is chemically stable, usually used as a coagulant, usually not used as an oxidizing agent, D does not meet the meaning of the question. D. Alum is chemically stable, usually used as a coagulant, not usually used as an oxidizing agent.

Question 10

Question 10: 13. The following description or operation of the experiment is incorrect.

13. The following description or operation of the experiment is incorrect.

A. A. Toothpaste contains water-insoluble ingredients, such as calcium carbonate, calcium phosphate, aluminum hydroxide, silicon dioxide, etc., which mainly play the role of friction agent
B. B. Paper chromatography usually uses filter paper as an inert support. Filter paper fibers are hydrophilic, and the water it adsorbs acts as the stationary phase
C. C. To check whether $\mathrm { CO } _ { 2 }$ is present in the gas from a burning match head, pass the gas through a sufficient amount of $\mathrm { NaHCO } _ { 3 }$ solution and clarified lime water in turn.
D. D. Decompression filtration should not be used to filter colloidal precipitates or precipitates with too small particles.

Answer

Answer: C

Solution: Burning a match produces $\mathrm { SO } _ { 2 }$ and $\mathrm { SO } _ { 2 }$ reacts with sodium bicarbonate to produce $\mathrm { CO } _ { 2 }$, so option C is wrong and the rest are correct, answer choice C.

Question 11

Question 11: 14. With the following device or apparatus to carry out the corresponding experiments, can not achie...

14. With the following device or apparatus to carry out the corresponding experiments, can not achieve the purpose of the experiment is ![](/images/questions/chem-experiment/image-001.jpg) (1) ![](/images/questions/chem-experiment/image-002.jpg) (2) ![](/images/questions/chem-experiment/image-003.jpg) (3) ![](/images/questions/chem-experiment/image-004.jpg) (4)

A. A. Preparation of $\mathrm { CO } _ { 2 }$ with device (1)
B. B. Separation of manganese dioxide and potassium chloride solution using device (2)
C. C. Preparation of bile alum crystals from saturated solution by evaporation of $\mathrm { CuSO } _ { 4 }$ using device (3)
D. D. Use device (4) to prepare NaCl solution of a certain concentration of material

Answer

Answer: C

Solution: A. Carbon dioxide is produced by reacting calcium carbonate with dilute hydrochloric acid, so using device (1) to produce $\mathrm { CO } _ { 2 }$ can achieve the purpose of the experiment, so A does not fit the question; B. Manganese dioxide is insoluble in water, potassium chloride is soluble in water, commonly used filtration method to separate the two, so the device (2) separation of manganese dioxide and potassium chloride solution can achieve the purpose of the experiment, so B is not consistent with the meaning of the question; C. evaporation $\mathrm { CuSO } _ { 4 }$ saturated solution of copper sulfate solid, can not prepare chalcocite crystals, the preparation of chalcocite crystals often $\mathrm { CuSO } _ { 4 }$ saturated solution evaporation of water, and then cooled to crystallization, filtration, so the C meets the meaning of the question; D. using volumetric flasks to prepare a certain amount of concentration of the solution, with the device (4) preparation of a certain amount of concentration of NaCl solution can achieve the purpose of the experiment, so D does not meet the meaning of the question. In summary, the answer is C.

Question 12

Question 12: 15. The following experimental design will accomplish the purpose of the experiment. | Select ...

15. The following experimental design will accomplish the purpose of the experiment. | Select Item | Purpose of experiment | Experimental design | | :---- | :--- | :--- | | A | Increase the oxidizing properties of $\mathrm { KMnO } _ { 4 }$ solution | Acidify $\mathrm { KMnO } _ { 4 }$ solution with oxalic acid | :--- | :--- | :--- | | B | remove acetic acid mixed with ethanol | add a suitable amount of $\mathrm { Na } _ { 2 } \mathrm { CO } _ { 3 }$ solution dropwise to the mixture and leave to partition | C | test for the oxidizing properties of sodium carbonate | add a suitable amount of $\mathrm { KMnO } _ { 4 }$ solution to the mixture and leave to partition | C | test whether sodium carbonate is mixed with sodium sulfite | add excess dilute hydrochloric acid to the sample, pass the resulting gas into $\mathrm { Ba } \left( \mathrm { NO } _ { 3 } \right) _ { 2 }$ solution and observe whether a white precipitate appears | D | verify that concentrated nitric acid is mixed with ethanol | add a drop of $\mathrm { Na } _ { 2 } \mathrm { CO } _ { 3 }$ solution to the mixture and let it stand for separation | D | verify that concentrated nitric acid can oxidize carbon monoxide under heating conditions | mix charcoal and concentrated nitric acid and heat, observe if a reddish brown gas appears |

A. A. A
B. B. B
C. C. C
D. D. D

Answer

Answer: C

Solution: A. Oxalic acid is reductive and will reduce potassium permanganate, A error; B.Ethanol and water are mutually soluble and cannot be separated into separate liquids; C. $\mathrm { CO } _ { 2 }$ does not react with acidified barium nitrate, but $\mathrm { SO } _ { 2 }$ can react with acidified barium nitrate to produce barium sulfate precipitate; D. Concentrated nitric acid can decompose by heat to produce $\mathrm { NO } _ { 2 }$, which is wrong; In summary, the answer is C.

Question 13

Question 13: 16. The following device or operation can achieve the purpose of the experiment is | device or oper...

16. The following device or operation can achieve the purpose of the experiment is | device or operation | ![](/images/questions/chem-experiment/image-005.jpg) | ![](/images/questions/chem-experiment/image-006.jpg) | | :--- | :--- | :--- | | :--- | :--- | :--- | Purpose of the experiment | A. Compare the metallic activities of Fe and Cr | B. Separate the $\mathrm { Fe } ( \mathrm { OH } ) _ { 3 }$ colloid from the $\mathrm { FeCl } _ { 3 }$ solution | :--- | :--- | :--- | :--- | :--- | :--- | :--- | :--- | | Apparatus or Operation | ![](/images/questions/chem-experiment/image-007.jpg) | ![](/images/questions/chem-experiment/image-008.jpg) | | Purpose of Experiment | C. Verifying the Reaction of Concentrated Ammonia with Concentrated Sulfuric Acid | D. Laboratory Preparation of Dilute Sulfuric Acid |

A. A. A
B. B. B
C. C. C
D. D. D

Answer

Answer: A

Solution: A. If the galvanometer pointer is deflected and bubbles escape from the chromium electrode, the metal activity of iron is stronger than that of chromium, and if the galvanometer pointer is deflected and bubbles escape from the iron electrode, the metal activity of chromium is stronger than that of iron, and A is correct; B. $\mathrm { Fe } ( \mathrm { OH } ) _ { 3 }$ colloid and $\mathrm { FeCl } _ { 3 }$ solution are able to pass through the filter paper, filtering with the filter paper can not separate the colloid and the solution, the application of semi-permeable membrane bag to do the separation of dialysis, B error; C. Concentrated sulfuric acid is not volatile, dipped in concentrated sulfuric acid glass rod near a glass rod dipped in concentrated ammonia, there can be no white smoke, C error; D. Preparation of solutions can not be diluted directly in the volumetric flask, D error.

Question 14

Question 14: 17. According to the experimental operation and phenomena, the following conclusions are correct | ...

17. According to the experimental operation and phenomena, the following conclusions are correct | Selected Item | Experimental Procedures and Phenomena | Conclusion | | :--- | :--- | :--- | | A | at room temperature will be inserted into a piece of iron dilute nitric acid and concentrated nitric acid, the former produces colorless gas, the latter no obvious phenomenon | dilute nitric acid oxidation than concentrated nitric acid | | B | A primary cell is made up of copper, silver and $\mathrm { AgNO } _ { 3 }$ solution. When connected, a silver-white metal is deposited on the surface of silver, and the solution near the copper electrode gradually turns blue. C | Add benzene to bromine water, shake and leave to stand, the water layer becomes lighter in color | Bromine reacts with benzene | D | Take a quantity of bromine and add it to the solution. | D | Take a sample of $\mathrm { Na } _ { 2 } \mathrm { SO } _ { 3 }$, dissolve it and add $\mathrm { BaCl } _ { 2 }$ solution, a white precipitate is produced. Add concentrated $\mathrm { HNO } _ { 3 }$ and there is still a precipitate | This sample contains SO 2- 4 |

A. A. A
B. B. B
C. C. C
D. D. D

Answer

Answer: B

Solution: A. Iron and dilute nitric acid reaction to produce nitric oxide gas, iron and concentrated nitric acid passivation, the greater the concentration of nitric acid the stronger the oxidizing properties, A error; B. Copper, silver and $\mathrm { AgNO } _ { 3 }$ solution composed of a primary cell, silver surface silver-white metal deposits, copper electrode near the solution gradually turn blue, copper electrode is the negative pole, silver is the positive pole, the metallicity of Cu is stronger than Ag, B correct; C. Add benzene to bromine water, bromine and benzene are mutually soluble, belonging to the extraction, is a physical change, not a chemical change, C error; D. Sodium sulfite and barium chloride react to produce barium sulfite precipitate, barium sulfite and nitric acid redox reaction to produce barium sulfate, so can not prove that the sample contains sulfate, D error;

Question 15

Question 15: 18. The corresponding operation of the following experiments is not reasonable. $\stackrel { \text ...

18. The corresponding operation of the following experiments is not reasonable. $\stackrel { \text { 工四分 } } { = }$ | A. Filtration in the purification of crude salt | B. Evaporation of potassium chloride solution | | :---- | :--- | | ![](/images/questions/chem-experiment/image-009.jpg) | ![](/images/questions/chem-experiment/image-010.jpg) | | C. Transfer of sodium sulfate solution | D. Absorption of ammonia and prevention of backsiphonage |

A. A. A
B. B. B
C. C. C
D. D. D

Answer

Answer: D

Solution: A. filtration separation of insoluble substances in crude salt, the key to the operation of "a stick", "two low", "three rely on", with a glass rod drainage, the operation is standardized, reasonable, A does not meet the question; B. KCl crystals from KCl solution, can be used to evaporate the crystallization method, evaporation and crystallization need to be stirred with a glass rod to prevent local overheating, resulting in liquid splashing, the operation is reasonable, B does not meet the meaning of the question; C. When transferring sodium sulfate solution to the volumetric flask, use a glass rod to divert the flow, the mouth of the beaker should be close to the glass rod, and the end of the glass rod should be inserted in the volumetric flask below the scale, the operation is reasonable, C does not meet the meaning of the question; D. Ammonia is very soluble in water, the funnel should be inverted above the liquid surface, the device funnel into the water can not prevent backsiphonage, D is consistent with the meaning of the question;

Question 16

Question 16: 19. The following experimental operations are incorrect

19. The following experimental operations are incorrect

A. A. During filtration, in order to make the filtration rate faster, a glass rod can be used to gently stir in the filter to accelerate the liquid flow
B. B. For distillation experiments, zeolite should be added to the distillation flask to prevent boiling over
C. C. When water and carbon tetrachloride iodine solution are divided, water is poured out of the upper port and carbon tetrachloride iodine solution flows out of the lower port.
D. D. For extraction, choose an extractant that is immiscible with the original solvent.

Answer

Answer: A

Solution: A. When filtering can not be stirred with a glass rod to avoid the filter paper broken, the filtrate turbid, so A error; B. In the heating of the liquid is easy to boil, can add zeolite, to avoid liquid boiling, so B correct; C. The density of carbon tetrachloride is greater than water, in the lower layer, liquid, water poured from the upper mouth, iodine solution of carbon tetrachloride out of the lower mouth, so C is correct; D. The extractant is not soluble in the original solvent, and the extracted material does not react, can achieve the purpose of separation, so D correct; answer A.

Question 17

Question 17: 20. In the table below, the reagents used to remove the impurities in the substance are the correct ...

20. In the table below, the reagents used to remove the impurities in the substance are the correct reagents and the correct method of operation (). | No. | Substance | Impurity | Reagent or method chosen for removing impurity | :--- | :--- | :--- | | :--- | :--- | :--- | :--- | :--- | (1) | $\mathrm { KNO } _ { 3 }$ solution | KOH | Add a viable amount of $\mathrm { FeCl } _ { 3 }$ solution and filter | | (2) | $\mathrm { FeSO } _ { 4 }$ solution | $\mathrm { CuSO } _ { 4 }$ | Add an excess of iron powder and filter | | (3) | $\mathrm { H } _ { 2 }$ | $\mathrm { CO } _ { 2 }$ | through a wash bottle containing a sufficient amount of NaOH solution, and then through a wash bottle containing concentrated sulphuric acid | | (4) | $\mathrm { NaNO } _ { 3 }$ | $\mathrm { CaCO } _ { 3 }$ | Dissolve, filter, evaporate |

A. A. (2) (3) (4)
B. B. (1) (3) (4)
C. C. (1) (2) (3)
D. D. (1) (2) (4)

Answer

Answer: A

Solution: (1) Addition of ferric chloride introduces impurity $\mathrm { Cl } ^ { - }$, so (1) is incorrect; (2) Addition of iron powder displaces copper, and copper and excess iron powder are removed by filtration, so (2) is correct; (3) Sodium hydroxide solution is used to absorb carbon dioxide gas and then concentrated sulfuric acid is used to dry the hydrogen gas, so (3) is correct; (4) Calcium carbonate is insoluble in water, dissolved after filtration to remove calcium carbonate, and then evaporate the filtrate can be obtained pure $\mathrm { NaNO } _ { 3 }$, so (4) is correct; In summary, (2) (3) (4) is correct, and A satisfies the question. The answer is A.

Question 18

Question 18: 21. The following statements are correct

21. The following statements are correct

A. A. Silver nitrate solution is kept in brown wide-mouth bottles to prevent decomposition in the presence of light
B. B. Determine the pH of a solution of $18 \mathrm {~mol} / \mathrm { L } \mathrm { H } _ { 2 } \mathrm { SO } _ { 4 }$ with pH paper.
C. C. During the dispensing operation, the lower liquid in the dispensing funnel is released from the lower port and the upper liquid is poured from the upper port
D. D. For extraction operations, an organic extractant should be chosen and the extractant must be less dense than water

Answer

Answer: C

Solution: A. Silver nitrate is easily decomposed by light and is kept in a brown bottle with a fine mouth, so A is wrong; B. $18 \mathrm {~mol} / \mathrm { L } \mathrm { H } _ { 2 } \mathrm { SO } _ { 4 }$ is concentrated sulfuric acid, which is dehydrating and can make pH test paper black, so it can't be read out, so B is wrong; C. Liquid separation operation, the lower layer of liquid in the liquid funnel from the lower mouth release, the upper layer of liquid from the mouth of the upper pour, so C is correct; D. extraction operation, the general choice of organic extractant, the density of the extractant does not require, so D error;

Question 19

Question 19: 22. Conduct the corresponding experiments with the following devices or operations to achieve the pu...

22. Conduct the corresponding experiments with the following devices or operations to achieve the purpose of the experiment ( ) | Options | A | B | | :--- | :--- | :--- | | Purpose | Explore the activity of iron, copper, and silver metals | Heat to decompose $\mathrm { NaHCO } _ { 3 }$ solids | | Apparatus or Operation | ![](/images/questions/chem-experiment/image-011.jpg) | ![](/images/questions/chem-experiment/image-012.jpg) | | Options | C | D | | Purpose | Conduct a flame-color test to determine if elemental sodium is present in a solid | Weigh a certain mass of NaOH solid | | Apparatus or Operation | ![](/images/questions/chem-experiment/image-013.jpg) | NaOH Solid |

A. A. A
B. B. B
C. C. C
D. D. D

Answer

Answer: C

Solution: A. investigate iron, copper, silver metal activity strength, through the experiment can be compared with Cu and Ag metallic strength, can not compare Fe and $\mathrm { Cu } , \mathrm { Ag }$ metal strength, A error; B. Sodium bicarbonate is a solid, the bottom of the test tube should be slightly higher than the mouth of the test tube, B error; C. Do the flame color test according to the diagram to observe the flame color of sodium, C is correct; D. Sodium hydroxide solid should be weighed in a beaker, D error;

Question 20

Question 20: 23. When conducting a chemical experiment, the following statements are true

23. When conducting a chemical experiment, the following statements are true

A. A. To prepare a small amount of dilute sulfuric acid solution, take a small amount of concentrated sulfuric acid and dilute it with water in a test tube.
B. B. If a small amount of alcohol misfires and burns, cover the flame with a wet rag.
C. C. Sucrose is a white crystal, non-toxic, and to investigate its sweetness, a small amount can be tasted from a reagent bottle
D. D. In order to save the experimental drugs, the remaining drugs in the experiment should be returned to the original bottle

Answer

Answer: B

Solution: A. The operation of diluting sulfuric acid is to inject a glass rod of concentrated sulfuric acid into water slowly, otherwise it will cause the acid to splash, so A is wrong; B.Covering the burning alcohol with a wet rag can isolate the alcohol from oxygen, and can play a role in cooling, so B is correct; C. Laboratory drugs are prohibited to taste, to prevent contamination of other toxic drugs, so although sucrose is non-toxic, but shall not be tasted, so the C. Wrong; D. The remaining experimental drugs can not be put back into the original reagent bottle to prevent contamination of drugs, so D error;

Question 21

Question 21: 24. The following removing reagents and separation methods are all correct | Options | Substances (...

24. The following removing reagents and separation methods are all correct | Options | Substances (impurities in parentheses) | Removing reagents | Separation methods | | :--- | :--- | :--- | :--- | :--- | | A | $\mathrm { Fe } ( \mathrm { Cu } )$ | Hydrochloric acid | Filtration | | B | $\mathrm { CO } _ { 2 }$ (HCl) | NaOH solution | gas washing | | :--- | :--- | :--- | :--- | :--- | | C | NaOH solution ( $\mathrm { Na } _ { 2 } \mathrm { CO } _ { 3 }$) | $\mathrm { Ca } ( \mathrm { OH } ) _ { 2 } \text { 溶液 }$ | add excess $\mathrm { Ca } ( \mathrm { OH } ) _ { 2 }$ solution | | D | $\mathrm { NaHCO } _ { 3 }$ solution ( $\mathrm { Na } _ { 2 } \mathrm { CO } _ { 3 }$ ) | $\mathrm { CO } _ { 2 }$ | pass excess $\mathrm { CO } _ { 2 }$ | | $\mathrm { CO } _ { 2 }$

A. A. A
B. B. B
C. C. C
D. D. D

Answer

Answer: D

Solution: A. Iron reacts with hydrochloric acid, copper does not react with hydrochloric acid, so that the mixture of iron and copper react with hydrochloric acid, will react with iron, copper will remain, can not remove copper, so A error; B. Carbon dioxide belongs to the acidic oxides, can react with sodium hydroxide solution, therefore, can not use sodium hydroxide solution as a reagent for the removal of impurities, you should use saturated sodium bicarbonate solution, so B error; C. Adding too much ${ } ^ { \mathrm { Ca } ( \mathrm { OH } ) _ { 2 } }$ solution will introduce calcium ions, so C is wrong; D. When carbon dioxide is added to a mixed solution of $\mathrm { Na } _ { 2 } \mathrm { CO } _ { 3 }$ and $\mathrm { NaHCO } _ { 3 }$, sodium carbonate reacts with carbon dioxide to form sodium bicarbonate, which is capable of removing impurities, so D is correct; The answer is D.

Question 22

Question 22: 25. The correct measures to be used in the following situations are ( )

25. The correct measures to be used in the following situations are ( )

A. A. If you get concentrated sulfuric acid on your skin, rinse immediately with plenty of sodium hydroxide solution.
B. B. Turn on the range hood immediately when you find a natural gas leak in your home
C. C. Small amount of sodium metal on fire, cover with dry sand
D. D. If a small amount of alcohol catches fire and burns, immediately douse with water

Answer

Answer: C

Solution: A. Concentrated sulfuric acid accidentally dripped on the hands, immediately wipe with a rag, and then rinse with a large amount of water, not with a large amount of sodium hydroxide solution first, A error; B. Combustible gases mixed with air in open flames have the danger of explosion, so found at home natural gas leaks, immediately open the hood, may cause an explosion, B error; C. Extinguish a small amount of burning sodium metal, covered with dry sand, isolated from oxygen, C is correct; D. Alcohol lamp accidentally overturned on fire, the application of wet rags cover extinguished, both can cool down, but also isolate the air, D error; Therefore, choose C.

Question 23

Question 23: 26. A group of liquid mixtures that can be separated with a separatory funnel is ( )

26. A group of liquid mixtures that can be separated with a separatory funnel is ( )

A. A. Bromine and benzene
B. B. Benzene and bromobenzene
C. C. Water and nitrobenzene
D. D. Benzene and gasoline

Answer

Answer: C

Solution: A. Bromine is soluble in benzene and cannot be partitioned, A error; B. Bromobenzene is soluble in benzene and cannot be separated, B is wrong; C. Nitrobenzene is insoluble in water and can be separated by liquid separation, C is correct; D. Benzene and gasoline are soluble in each other and cannot be separated, D is wrong; The correct answer is C.

Question 24

Question 24: 27. Artificial carnallite ( $\mathrm { KCl } \cdot \mathrm { MgCl } _ { 2 } \cdot 6 \mathrm { H } _ ...

27. Artificial carnallite ( $\mathrm { KCl } \cdot \mathrm { MgCl } _ { 2 } \cdot 6 \mathrm { H } _ { 2 } \mathrm { O }$) is an intermediate product of salt chemical production. To produce magnesium metal from carnallite, the following steps can be performed: (1) filtration (2) dissolution (3) addition of an appropriate amount of $\mathrm { Ca } ( \mathrm { OH } ) _ { 2 }$ (4) evaporation (5) dissolution in hydrochloric acid (6) electrolysis of the molten $\mathrm { MgCl } _ { 2 } ( 7 )$ crystals of strongly heated $\mathrm { MgCl } _ { 2 } \cdot 6 \mathrm { H } _ { 2 } \mathrm { O }$ in an HCl air stream in the correct order ( ). order of the crystals is ( )

A. A. (5) (3) (1) (2) (4) (6) (7)
B. B. (2) (3) (1) (5) (4) (7) (6)
C. C. (2) (4) (1) (3) (7) (5) (6)
D. D. (5) (3) (1) (4) (2) (7) (6)

Answer

Answer: B

Solution: The steps of purifying carnallite to get $\mathrm { MgCl } _ { 2 }$ are: first dissolve carnallite in water, because $\mathrm { KCl } , \mathrm { MgCl } _ { 2 }$ are soluble in water, and then precipitate $\mathrm { Mg } ^ { 2 + }$; because the solubility of $\mathrm { Mg } ( \mathrm { OH } ) _ { 2 }$ is smaller than $\mathrm { Ca } ( \mathrm { OH } ) _ { 2 }$, so add appropriate $\mathrm { Ca } ( \mathrm { OH } ) _ { 2 }$ and filter it to get $\mathrm { Mg } ( \mathrm { OH } ) _ { 2 }$, and then wash it. _FORMULA_4]] is smaller than $\mathrm { Ca } ( \mathrm { OH } ) _ { 2 }$, so $\mathrm { Mg } ( \mathrm { OH } ) _ { 2 }$ is obtained after filtration by adding an appropriate amount of $\mathrm { Ca } ( \mathrm { OH } ) _ { 2 }$, and $\mathrm { Mg } ( \mathrm { OH } ) _ { 2 }$ is obtained after washing and dissolving it in an appropriate amount of hydrochloric acid for the reaction of $\mathrm { Mg } ( \mathrm { OH } ) _ { 2 } + 2 \mathrm { HCl } = \mathrm { MgCl } _ { 2 } + 2 \mathrm { H } _ { 2 } \mathrm { O }$, $\mathrm { MgCl } _ { 2 } \cdot 6 \mathrm { H } _ { 2 } \mathrm { O }$ is obtained by evaporation and crystallization. In the process of heating $\mathrm { MgCl } _ { 2 } \cdot 6 \mathrm { H } _ { 2 } \mathrm { O }$, $\mathrm { MgCl } _ { 2 }$ will be hydrolyzed to $\mathrm { Mg } ( \mathrm { OH } ) _ { 2 }$, and the hydrolysis of $\mathrm { MgCl } _ { 2 }$ is a reversible reaction, $\mathrm { MgCl } _ { 2 } + 2 \mathrm { H } _ { 2 } \mathrm { O } \rightleftharpoons \mathrm { Mg } ( \mathrm { OH } ) _ { 2 } + 2 \mathrm { HCl }$. According to the principle of equilibrium shift, the hydrolysis of $\mathrm { Mg } ^ { 2 + }$ was inhibited by heating $\mathrm { Mg } ^ { 2 + }$ in an HCl gas stream, and pure $\mathrm { MgCl } _ { 2 }$ was obtained, and finally magnesium metal was obtained by electrolytic melting of $\mathrm { MgCl } _ { 2 }$. . In summary, the steps are (2) (3) (1) (5) (4) (7) (6), so choose B.

Question 25

Question 25: 28. The following experiments, according to the experimental operation and the phenomenon of the con...

28. The following experiments, according to the experimental operation and the phenomenon of the conclusion obtained is correct ( ) | Options | Experimental Operations Experimental Phenomena | Experimental Conclusions | | :--- | :--- | :--- | | A | Red-hot charcoal thrown into concentrated nitric acid produces a reddish-brown gas | Charcoal reacts with concentrated nitric acid under heating conditions to form $\mathrm { NO } _ { 2 }$ | | B | Heating a test tube containing $\mathrm { NH } _ { 4 } \mathrm { Cl }$ solids, the solids disappear from the bottom of the test tube and crystals condense at the mouth of the test tube | $\mathrm { NH } _ { 4 } \mathrm { Cl }$ the solids sublimate by heat | | C | Add a small amount of $\mathrm { CuSO } _ { 4 } \cdot 5 \mathrm { H } _ { 2 } \mathrm { O }$ to a surface dish and add | Concentrated sulfuric acid is absorbent | | The solid changes color from blue to colorless. | :--- | :--- | :--- | D | | Add ${ } ^ { 2 m L }$ acidic $^ { \mathrm { KMnO } _ { 4 } }$ solution to a test tube, pass enough $\mathrm { SO } _ { 2 }$ gas through it and the solution discolors | $\mathrm { SO } _ { 2 }$ is bleaching |

A. A. A
B. B. B
C. C. C
D. D. D

Answer

Answer: C

Solution: A. When red-hot charcoal is added to concentrated nitric acid, a reddish-brown gas is produced, which may be nitrogen dioxide obtained by decomposition of concentrated nitric acid under heat, not necessarily carbon reacting with concentrated nitric acid to produce ${ } ^ { \mathrm { NO } _ { 2 } } , \mathrm {~A}$ Error; B. $\mathrm { NH } _ { 4 } \mathrm { Cl }$ decomposes into $\mathrm { NH } _ { 3 }$ and HCl under heat, and cools down at the mouth of the test tube. $\mathrm { NH } _ { 3 }$ reacts with HCl to obtain $\mathrm { NH } _ { 4 } \mathrm { Cl }$ solid, which does not indicate that the reaction of $\mathrm { NH } _ { 4 } \mathrm { Cl }$ with $\mathrm { NH } _ { 4 } \mathrm { Cl }$ does not result in the formation of nitrogen dioxide. FORMULA_5]] solid can be sublimated; C. Add a small amount of cholecalciferol to the surface dish, then add about 3 mL of concentrated sulfuric acid, stir, the solid changes from blue to white proving that the concentrated sulfuric acid is water-absorbent, C is correct; D. Acidic potassium permanganate solution has a strong oxidizing, can oxidize reducing substances, to acidic potassium permanganate solution into sulfur dioxide, the solution discoloration, reflecting the sulfur dioxide reducing, D error; Answer choice C.

Question 26

Question 26: 29. Safety awareness in chemical experiments is an important scientific literacy, the following expe...

29. Safety awareness in chemical experiments is an important scientific literacy, the following experimental operations are incorrect ( )

A. A. Sodium is a very dangerous metal, after doing the experiment, the remaining sodium should be put into the waste liquid tank
B. B. Sodium fires cannot be extinguished with foam fire extinguishers
C. C. Liquid chlorine can be stored in sealed cylinders
D. D. Chlorine gas is toxic and needs to be prepared in a lab fume hood

Answer

Answer: A

Solution: A. Sodium is a very dangerous metal, after the experiment, the remaining sodium should be put back to the original reagent bottle, so A error; B. Sodium can react with water, sodium fire can not be used to foam fire extinguishers, sodium fire should be covered with sand to extinguish, so B is correct; C. At room temperature, iron and chlorine do not react, liquid chlorine can be sealed and stored in cylinders, so C is correct; D. Chlorine gas is toxic, in order to prevent poisoning, need to prepare chlorine gas in the laboratory fume hood, so D is correct;

Question 27

Question 27: 30. The textbook contains the following seven simple icons used to remind of experiment safety, the ...

30. The textbook contains the following seven simple icons used to remind of experiment safety, the following related statements are wrong ( ) ![](/images/questions/chem-experiment/image-014.jpg) Goggles (1) ![](/images/questions/chem-experiment/image-015.jpg) Wash your hands (2) ![](/images/questions/chem-experiment/image-016.jpg) use electricity (3) ![](/images/questions/chem-experiment/image-017.jpg) exhaust (4) ![](/images/questions/chem-experiment/image-018.jpg) Heat㳷 (5) ![](/images/questions/chem-experiment/image-019.jpg) Open fire (6) ![](/images/questions/chem-experiment/image-020.jpg) Sharp objects (7) Full reminder signs (1) (2) (5) (6)

A. A. Studying the reaction of methane with chlorine gas, this experiment involves safety reminder signs (1) (2) (3) (7)
B. B. Compare the thermal stability of $\mathrm { Na } _ { 2 } \mathrm { CO } _ { 3 }$ and $\mathrm { NaHCO } _ { 3 }$ by heating $\mathrm { Na } _ { 2 } \mathrm { CO } _ { 3 }$ and $\mathrm { NaHCO } _ { 3 }$ separately, which involves a safe and reliable method of heating the $\mathrm { Na } _ { 2 } \mathrm { CO } _ { 3 }$ and $\mathrm { NaHCO } _ { 3 }$.
C. C. The reaction of starch with iodine is used to test whether starch is completely hydrolyzed, and the experiment involves safety reminder signs (1) (2) (5) (6)
D. D. Cut a piece of sodium metal the size of a green bean and heat it in air, this experiment involves safety reminder signs (1) (2) (4) (5) (6) (7)

Answer

Answer: A

Solution: A. The reaction between methane and chlorine requires light, possibly with an electric light source involving (3), goggles (1)), and hand washing (②), but chlorine is poisonous and requires exhaust (4), and sharps (7) are not needed, A. Wrong; B. Heating solids requires goggles (①), hand washing (②), hot iron (5), open flame (6), B is correct; C. Starch hydrolysis requires heating conditions, so there are hot (5) and open flame (6), but also need goggles (1), hand washing (2), C is correct; D. Sodium heating needs goggles (①), hand washing (②), exhaust (④), hot iron (5), open flame (6), sharp objects (7), cutting sodium with a knife), D is correct.

Question 28

Question 28: 31. The following substances can be separated by the method of liquid partitioning ( )

31. The following substances can be separated by the method of liquid partitioning ( )

A. A. Gasoline and kerosene
B. B. Ethanol and water
C. C. Acetic acid and ethanol
D. D. Ethyl acetate and sodium carbonate solution

Answer

Answer: D

Solution: A. Gasoline and kerosene are mutually soluble and should be separated by distillation, A error; $\mathrm { B } ,$ Ethanol and water are mutually soluble and should be separated by distillation, B error; C, acetic acid and ethanol are mutually soluble and should be separated by distillation, C error; D. Ethyl acetate and sodium carbonate solution are not mutually soluble and can be separated by partitioning, D is correct;

Question 29

Question 29: 32. Chlorine and its compounds are widely used in daily life, and chlorine gas is an important raw m...

32. Chlorine and its compounds are widely used in daily life, and chlorine gas is an important raw material for the preparation of chlorine-containing compounds. The following experimental setups or operations for chlorine gas can achieve the purpose of the experiment ( ). | A | B | C | D | | :--- | :--- | :--- | :--- | :--- | | ![](/images/questions/chem-experiment/image-021.jpg) | ![](/images/questions/chem-experiment/image-022.jpg) | ![](/images/questions/chem-experiment/image-023.jpg) | ![](/images/questions/chem-experiment/image-024.jpg) | :--- | :--- | :--- | :--- | :--- | :--- | :--- | :--- | :--- | :--- | :--- | :--- | :--- | | generate $\mathrm { Cl } _ { 2 }$ | ![](/images/questions/chem-experiment/image-025.jpg) | ![](/images/questions/chem-experiment/image-026.jpg) | measure pH of chlorinated water |

A. A. A
B. B. B
C. C. C
D. D. D

Answer

Answer: C

Solution: A. Manganese dioxide reacts with concentrated hydrochloric acid to make chlorine gas; B.Chlorine gas and HCl will react with saturated sodium bicarbonate; C. The oxidizing property of $\mathrm { Cl } _ { 2 }$ is stronger than that of $\mathrm { Br } _ { 2 }$, so $\mathrm { C } _ { 2 } 2$ can be oxidized to obtain bromine monomers by passing into the solution containing $\mathrm { Br } ^ { - }$, and $\mathrm { Cl } _ { 2 }$ is a pollutant, which needs exhaust treatment. pollutant, need to be tail gas treatment, C is correct; D. Chlorine water contains hypochlorous acid has bleaching, can make the test paper discoloration, so the pH value of chlorine water can not be measured with pH test paper, D error;

Question 30

Question 30: 33. The following statements are correct ()

33. The following statements are correct ()

A. A. Sodium metal is usually kept in kerosene in the laboratory and cannot be put back into the original reagent bottle when there is sodium metal left in the experiment.
B. B. Freshly prepared chlorine water should be stored in clear glass reagent bottles
C. C. Alcohol, sodium, etc. can be extinguished with water.
D. D. In case of chlorine gas leakage, cover your nose and mouth with a wet towel soaked in $\mathrm { Na } _ { 2 } \mathrm { CO } _ { 3 }$ solution and take shelter upwind.

Answer

Answer: D

Solution: A. Sodium is denser than kerosene and does not react with kerosene, and metallic sodium is usually kept in kerosene in the laboratory. When there are lumps of sodium metal remaining in the experiment, it should be put back into the original reagent bottle, and if a small amount of sodium crumbs remain, dissolve them away with alcohol, A is incorrect; B. Hypochlorous acid in chlorine water is easy to decompose in the presence of light, freshly made chlorine water should be kept in brown glass reagent bottles, B is incorrect; C. Alcohol dissolved in water can still burn, sodium combustion products $\left( \mathrm { Na } _ { 2 } \mathrm { O } _ { 2 } \right)$ can be reacted with water to produce $\mathrm { O } _ { 2 }$ can be flammable, can not be extinguished with water, C is not correct; D. Chlorine can react with $\mathrm { Na } _ { 2 } \mathrm { CO } _ { 3 }$ solution, and chlorine is denser than air. If chlorine leaks, cover your nose and mouth with a wet towel moistened with $\mathrm { Na } _ { 2 } \mathrm { CO } _ { 3 }$ solution, and take shelter upwind;

Question 31

Question 31: 34. The following experimental maneuvers or devices will accomplish the purpose () | A | B | C | D ...

34. The following experimental maneuvers or devices will accomplish the purpose () | A | B | C | D | | :--- | :--- | :--- | :--- | | ![](/images/questions/chem-experiment/image-027.jpg) | ![](/images/questions/chem-experiment/image-028.jpg) | ![](/images/questions/chem-experiment/image-029.jpg) | ![](/images/questions/chem-experiment/image-030.jpg) | | mix concentrated sulfuric acid and ethanol | prepare a solution of a certain concentration | collect ${ } ^ { \mathrm { NO } _ { 2 } }$ gas | prove that acetylene discolors bromine water |

A. A. A
B. B. B
C. C. C
D. D. D

Answer

Answer: B

Question 32

Question 32: 35. The following experimental operations or descriptions of experimental facts are correct ( )

35. The following experimental operations or descriptions of experimental facts are correct ( )

A. A. If a burning alcohol lamp is accidentally knocked over and catches fire, immediately cover it with a damp cloth to extinguish it.
B. B. The volumetric flask in which the solution is prepared should be moistened with the solution to be prepared.
C. C. When preparing sulfuric acid solution, add a certain volume of water to the measuring cylinder, then slowly add concentrated sulfuric acid with stirring
D. D. When weighing with a balance, all drugs weighed are placed on the weighing paper and weighed

Answer

Answer: A

Solution: A. Remove combustibles, isolate oxygen or reduce the temperature to below the ignition point can extinguish the fire, wet cloth cover can reduce the temperature to below the ignition point and can isolate the air, so A correct; B. Rinse the volumetric flask with the solution to be prepared, so that the concentration is large, can not be used to prepare the solution to rinse, so B is wrong; C. can not be dissolved in a volumetric flask, dilution, preparation of sulfuric acid solution, you can first add a certain volume of water in the beaker to prevent splashing liquid, and then slowly add concentrated sulfuric acid under stirring, so C error; D. NaOH has a water-absorbent, can react with carbon dioxide in the air, weighing should minimize the contact area with the air, should be placed in a small beaker weighing, so D error;

Question 33

Question 33: 37. The following options for obtaining substances from the oceans do not make sense.

37. The following options for obtaining substances from the oceans do not make sense.

A. A. Crude salt is first decontaminated and refined to obtain saturated brine, then electrolyzed to obtain chlorine gas, and finally reacted with milk of lime to produce bleaching powder.
B. B. Bromine water is obtained by passing chlorine gas through the acidification of brine, then it is passed into an aqueous solution of $\mathrm { SO } _ { 2 }$ with hot air, and finally crude bromine is obtained by distillation after passing chlorine gas through the solution.
C. C. Dried kelp is cauterized and extracted with water, then $\mathrm { H } _ { 2 } \mathrm { O } _ { 2 }$ is added to obtain iodine water, and finally iodine monomers are obtained by extraction, fractionation, and distillation
D. D. Add alum to the seawater introduced into the reservoir, and the alum can react with the water to produce colloids after ionization, so that you can obtain relatively pure drinking water.

Answer

Answer: D

Solution: A. Crude salt contains sediment, $\mathrm { Ca } ^ { 2 + } , \mathrm { Mg } ^ { 2 + } , \mathrm { SO } ^ { 2 - }$ and other impurities, first add $\mathrm { BaCl } _ { 2 } , \mathrm { Na } _ { 2 } \mathrm { CO } _ { 3 }$, NaOH to remove $\mathrm { SO } ^ { 4 } , \mathrm { Ca } ^ { 2 + } , \mathrm { Mg } ^ { 2 + }$, and then filtration to remove the sediment and precipitation, and finally add dilute hydrochloric acid to adjust the pH, to remove the excessive $\mathrm { Na } _ { 2 } \mathrm { CO } _ { 3 } , \mathrm { NaOH }$, so as to obtain refined saturated brine, and then electrolysis to obtain chlorine gas, that is: $2 \mathrm { NaCl } + 2 \mathrm { H } _ { 2 } \mathrm { O }$. FORMULA_3]], so as to obtain refined saturated brine, and then electrolyze to obtain chlorine gas, that is: $2 \mathrm { NaCl } + 2 \mathrm { H } _ { 2 } \mathrm { O }$ $\xlongequal { \text { electrolysis } } 2 \mathrm { NaOH } + \mathrm { H } _ { 2 } \uparrow + \mathrm { Cl } _ { 2 } \uparrow$, and the resulting $\mathrm { Cl } _ { 2 }$ reacts with milk of lime to produce bleach, i.e., $2 \mathrm { Cl } _ { 2 } + 2 \mathrm { Ca } ( \mathrm { OH } ) _ { 2 } = \mathrm { CaCl } _ { 2 } + \mathrm { Ca } ( \mathrm { ClO } ) _ { 2 } + 2 \mathrm { H } _ { 2 } \mathrm { O }$, A is correct; B. Bitter brine contains $\mathrm { Br } ^ { - }$, which is acidified and passed through chlorine gas to obtain bromine water ($\mathrm { Cl } _ { 2 } + 2 \mathrm { Br } ^ { - } = 2 \mathrm { Cl } ^ { - } + \mathrm { Br } _ { 2 }$), and then passed through hot air to $\mathrm { SO } _ { 2 }$ aqueous solution ($\mathrm { Br } _ { 2 } + \mathrm { SO } _ { 2 } + 2 \mathrm { H } _ { 2 } \mathrm { O } = \mathrm { H } _ { 2 } \mathrm { SO } _ { 4 } + 2 \mathrm { HBr }$), and finally passed through chlorine gas to obtain crude bromine ($\mathrm { SO } _ { 2 }$). Finally, chlorine is added and distilled to obtain crude bromine ( $2 \mathrm { HBr } + \mathrm { Cl } _ { 2 } = 2 \mathrm { HCl } + \mathrm { Br } _ { 2 }$), B is correct; C. Dried kelp is cauterized and leached with water to obtain a solution containing iodine ions, then $\mathrm { H } _ { 2 } \mathrm { O } _ { 2 }$ is added to obtain iodine water, and finally iodine monomers are obtained by extraction, partitioning, and distillation, C is correct; D. Alum ionization can react with water to produce colloids just adsorption of suspended impurities in water precipitation, can not remove seawater in the $\mathrm { Mg } ^ { 2 + } , \mathrm { Na } ^ { + } , \mathrm { Br } ^ { - } , \mathrm { Cl } ^ { - }$ plasma, can not get more pure drinking water, D error;

Question 34

Question 34: 38 . The following graphical experiment is correct ![](/images/questions/chem-experiment/image-031....

38 . The following graphical experiment is correct ![](/images/questions/chem-experiment/image-031.jpg)

A. A. Separation of benzene and $\mathrm { CCl } _ { 4 }$
B. B. Decomposition of sodium bicarbonate by heat
C. C. Removal of $\mathrm { CO } _ { 2 }$ gas from CO gas
D. D. Preparation of small amounts of distilled water

Answer

Answer: D

Solution: A. Benzene and $\mathrm { CCl } _ { 4 }$ are mutually soluble and cannot be separated by liquid separation, but should be distilled, A error; B. When heating solids, the mouth of the test tube should be tilted slightly downward to prevent condensate from flowing back and blowing up the test tube, and the mouth of the test tube is tilted upward in the picture, which is wrong; C. Remove CO in the $\mathrm { CO } _ { 2 }$, the gas should be long in and short out in order to fully contact with the NaOH solution, the inlet catheter in the figure is too short, C error; D. distillation device, the thermometer mercury ball in the mouth of the branch pipe, condensate down into the upper out, the device is correct, D is correct; D. answer choice.

Question 35

Question 35: 39. Chemistry is closely related to production and life. The following statements are correct ( )

39. Chemistry is closely related to production and life. The following statements are correct ( )

A. A. Soaking Chili Peppers in Canola Oil Involves Extraction Knowledge
B. B. Glass containers can hold various acids for a long time
C. C. Ammonia is used as a refrigerant because it is very soluble in water.
D. D. Deep burial of waste batteries prevents heavy metal pollution

Answer

Answer: A

Solution: A. Organic substances are easily soluble in organic solvents, canola oil is a fat, can dissolve organic substances in chili peppers, so soaking chili peppers in canola oil involves extraction knowledge, A is correct; B. Glass contains silica, $\mathrm { SiO } _ { 2 }$ can react with hydrofluoric acid, so glass containers can not hold hydrofluoric acid, B error; C. The use of liquid ammonia as a refrigerant is because liquid ammonia gasification will absorb a lot of heat from the surrounding environment, so that the temperature of the environment is lowered, and ammonia is very soluble in water has nothing to do with the nature of the C error; D. Waste batteries contain heavy metals, if the waste batteries buried deep, will lead to soil pollution, water pollution, D error; Therefore, the reasonable option is A.

Question 36

Question 36: 40. The following experimental operations or descriptions are not correct. High School Chemistr...

40. The following experimental operations or descriptions are not correct. High School Chemistry Assignment, October 31, 2025

A. A. The mixture of $\mathrm { NaNO } _ { 3 }$ and KCl is heated and concentrated until crystals precipitate, and NaCl crystals are separated when filtered while hot.
B. B. Aluminum containers cannot be used for pickles because chloride ions destroy the oxide film on the aluminum surface.
C. C. Add enough saturated NaF solution to $\mathrm { AlCl } _ { 3 }$ solution, then add a few drops of ammonia, no obvious phenomenon.
D. D. In the experiment of separating iron and copper ions by paper chromatography, the filter paper was dried after spotting, and then the specimen spots were immersed in the unfolding agent

Answer

Answer: D

Solution: A. The solubility of sodium chloride is not changed much by temperature, and the solubility of potassium chloride rises with the increase of temperature, which can be realized by heating concentration and cooling crystallization method to separate sodium chloride and potassium chloride, so A is correct; B. Chlorine ions will destroy the oxide film on the surface of aluminum, resulting in aluminum corrosion, then can not use aluminum containers to pickles, etc., so B is correct; C. $\mathrm { Al } ^ { 3 + }$ combines more easily with $\mathrm { F } ^ { - }$ to form $\mathrm { AlF } ^ { 6 }$ and does not react with $\mathrm { NH } _ { 3 } \cdot \mathrm { H } _ { 2 } \mathrm { O }$, so C is correct; D. Since $\mathrm { Cu } ^ { 2 + }$ and $\mathrm { Fe } ^ { 3 + }$ move at different speeds, after a period of time, $\mathrm { Cu } ^ { 2 + }$ and $\mathrm { Fe } ^ { 3 + }$ will be different distances from the starting point, so as to achieve the purpose of separation, take a sample of the solution with a capillary tube. Take the sample solution with a capillary tube, gently dot the sample on the origin, let it dry, and repeat 3-5 times before immersing it in the unfolding agent, so D is wrong;

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