Testing and Identifying Substances

How the real exam tests it

Questions from real CSCA papers that test this concept. Work each one out before you open the answer.

1. CSCA Chemistry December 2025 Past Paper
   In the flame test with sodium chloride, the flame color is ( )
   • A. Pale white
   • B. Yellow
   • C. Light blue
   • D. Green
   Show answer & solution

   Answer: B

   Answer: B Na⁺ gives a bright yellow flame in the flame test (a standard fact to memorize).
   See it in the full CSCA Chemistry December 2025 Past Paper
2. CSCA Chemistry April 2026 Past Paper
   Which of the following salts produces a violet flame in a flame test? ( )
   • A. $\mathrm{CaCl_{2}}$
   • B. KCl
   • C. $\mathrm{Na_{2}SO_{4}}$
   • D. $\mathrm{CuCl_{2}}$
   Show answer & solution

   Answer: B

   Answer: B Potassium produces a violet flame in a flame test (viewed through blue cobalt glass).
   Take the full CSCA Chemistry April 2026 Past Paper — timed & graded
3. CSCA Chemistry March 2026 Past Paper
   A substance produces a yellow flame in a flame test. It must contain
   • A．Sodium
   • B．Potassium
   • C．Calcium
   • D．Copper
   Show answer & solution

   Answer: A

   Yellow flame $=$ sodium. Answer: $A$.
   Take the full CSCA Chemistry March 2026 Past Paper — timed & graded