Waec Chemistry 1992 Past Questions and Answers

Question 51:

• WAEC 1992

(a)(i) State Graham's law of diffusion.
(ii) Consider the reaction represented by the following equation:
N\(_2\)O\(_{4(g)}\) 2NO\(_{2(g)}\)
Night yellow dark brown
State what would happen to the vapour density of N\(_2\)O\(_4\) as the temperature of the system is increased. If the system is cooled, would the gases become lighter or darker in colour? Explain your answer in each case.

(b) Explain the following observations:
(i) an inflated balloon that was left in the sun. burst after some time;
(ii) a pure sample of a liquid did not have a constant boiling point at the top and at the base of a high mountain

(c)(i) List two gaseous reducing agents
(ii) Write one equation each to illustrate the reducing property of the gases you listed in (c)(i) above.