Section A
Q1.
(a)
Explain why—
(i) the bond angle in F2O is smaller than that in H2O;
(ii) certain substances like CO and N2O are associated with residual entropy even at 0 K.
(b)
(i) Assuming that the activation energy and pre-exponential factor are temperature independent, obtain the expression relating the activation energy (Ea) and the rate parameters k(T1) and k(T2) for the same reaction at temperatures T1 and T2.
(ii) Calculate the ionic strength of a solution that contains 0.01 \text mol kg-1 H2SO4 and 0.02 mol kg^-1 sodium chloride.
(c)
The heat of the reaction
Fe2O3(s) + 3 H2(g) → 2 Fe (s) + 3 H2O(l)
at 25 °C was found to be -8.4 kcal. What will be the heat of the reaction at 120 °C? The molar heat capacities at constant pressure and at 25 °C for iron oxide, hydrogen, iron and water are 25.0 cal deg^-1 mol^-1, 6.9 cal deg^-1 mol^-1, 6.1 cal deg^-1 mol^-1 and 18.0 cal deg^-1 mol^-1 respectively.
(d)
(i) How many crystal systems are there? Name the crystal systems wherein the unit cell axes are mutually perpendicular. Give one example in each case.
(ii) What is the equation for the distance between the planes (110) for a crystal with mutually perpendicular axes?
