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JAMB Chemistry 1986 Question 33

Question 33

Acids, Bases and Salts

A substance Z reacts with NaOH to give salt and water only. When Z is treated with dilute HCl, a gas is evolved which gives a yellow suspension on passing into concentrated H2SO4. Substance Z is

  1. A.NaHS
  2. B.Na2SO3
  3. C.Na2S
  4. D.NaHSO3
Show the answer and explanation

Answer: A (NaHS)

Explanation

Z reacts with NaOH, so it is an acid salt. With HCl it gives H2S, which concentrated H2SO4 oxidises to yellow sulphur, so Z is NaHS.