passwella.
Menu

JAMB Chemistry 1978 Question 44

Question 44

Chemical Formulae and Equations

An experimental test of the Law of Conservation of Mass is illustrated in the diagram. In practice, the flask is weighed before and after reaction between solutions X and Y. Which of the following pairs of solutions will be unsuitable for the experiment?

Diagram for this question
  1. A.X = hydrochloric acid; Y = silver nitrate
  2. B.X = barium chloride Y = dilute sulphuric acid
  3. C.X = hydrochloric acid; Y = sodium hydroxide
  4. D.X = hydrochloric acid; Y = lead nitrate
  5. E.X = hydrochloric acid; Y = sodium carbonate
Show the answer and explanation

Answer: E (X = hydrochloric acid; Y = sodium carbonate)

Explanation

Hydrochloric acid and sodium carbonate give off carbon dioxide gas, which can escape or build up pressure and push out the stopper, so the mass may not stay the same. The other pairs form only precipitates or water.