(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.
Explanation
(a)(i) Graham's Law of diffusion states that the rate of diffusion of a gas is inversely related r to the square root of the density of the gas
(ii) The density becomes lighter. If the system is cooled, the product becomes lighter in colour. In each of the above answers. nitrogen(IV) is specimen and the second specimen is dinitrogen tetraoxide
(b)(i) The air in the balloon expanded as the temperature is increased
(ii) At the top of the mountains, the pressure is lower than the atmospheric pressure which prevails at the base of tile mountain, such that the liquid starts bubbling or boiling at lower temperature than that obtained at base of the mountain.
(c)(i) Two gaseous reducing agents are carbon(II) oxide and sulphur (IV) oxide.
(ii) 3CO\(_{(g)}\) + Fe\(_2\)O\(_3\) \(\to\) 2Fe\(_{(s)}\) + 3CO\(_{2(s)}\);
SO\(_{2(g)}\) + 2HNO\(_{3(aq)}\) --> H\(_2\)SO\(_{4(aq)}\) + 2NO\(_{2(g)}\)