Section A
Q1.
(a)
A gas mixture has the following composition by volume : C2H4 = 50\%, C2H6 = 35\% and CH4 = 15\%. Calculate :
(i) Average molecular weight.
(ii) The composition of the gas in weight %.
(iii) The density of the gas mixture in kg/m3 at 25°C and 1 atm.
(b)
If 5 kg of methanol and 2 kg of NH3 are reacted to form 2.5 kg of CH3NH2 by the reaction :
CH3OH + NH3 longrightarrow CH3NH2 + H2O
determine :
(i) the limiting reactant
(ii) excess reactant and its percentage
(iii) degree of completion.
(c) Prove that Joule - Thompson coefficient of an ideal gas is zero.
(d)
The heterogeneous gas phase reaction A + B ightarrow R + S, catalyzed by a solid takes place according to the following mechanism :
A(g) + sigma ightleftharpoons Asigma (Chemisorption of A)
Asigma + B(g) ightleftharpoons Rsigma + S(g) (Surface reaction)
Rsigma Rightarrow R(g) + sigma (Desorption of R)
Derive an expression for the rate of disappearance of A, assuming surface reaction step as rate limiting.
(sigma, (Sigma) active site).
(e) Calculate the bubble-point pressure and dew-point pressure of an equimolar mixture of benzene and toluene at 100°C. The vapour pressures of benzene and toluene at 100°C are 1344 mm Hg and 554.8 mm Hg respectively. Assume the Raoult's law to be valid.
