JAMB Chemistry Past Questions & Answers - Page 322

1,608.

An experiment 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 experiments

A.

X = hydrochloric acid; Y = silver nitrate

B.

X = barium chloride; Y = dilute sulphuric acid

C.

X = hydrochloric acid; Y = sodium hydroxide

D.

X = hydrochloric acid; Y = lead nitrate

E.

X = hydrochloric acid; Y = sodium carbonate

Correct answer is E

No explanation has been provided for this answer.

1,610.

A solid X when heated gives off a brown gas. If X is soluble in excess sodium hydroxide solution but insoluble in excess ammonium hydroxide solution, then X is

A.

basic lead carbonate

B.

lead (II) nitrate

C.

sodium carbonate

D.

zinc nitrate

E.

sodium nitrate

Correct answer is B

Lead nitrate reacts with ammonium hydroxide solution to form a white precipitate. This white precipitate does not dissolve in excess ammonium hydroxide.