What is the entropy change for the reaction given below,
2H2 (g) + O2 (g) 2H2O(l)
at temperature 300 K? Standard entropies of H2 (g), O2(g) and H2O(l) are 126.6, 201.20 and 68.0 JK-1mol-1 respectively.
(a) -318.4 JK-1mol-1 (b) 318.4 JK-1mol-1
(c) 31.84 JK-1mol-1 (d) none of these
If S for H2, Cl2 and HCl are 0.13, 0.22 and 0.19 kJ K-1mol-1 respectively. The total change in standard entropy for the reaction, H2 + Cl2 2HCl is:
(a) 30 J K-1mol-1 (b) 40 J K-1mol-1
(c) 60 J K-1mol-1 (d) 20 J K-1mol-1
The direct conversion of A to B is difficult and thus it is converted by path ACDB. Given
Where e.u. is the entropy unit, then is:
(a) +60 e.u (b) +100 e.u
(c) -60 e.u (d) -100 e.u
Concept Questions :-
In a flask, colourless N2O4(g) is in equilibrium with brown coloured NO2(g). At equilibrium when the flask is heated to 100C, the brown colour deepens and on cooling it becomes coloured. Which statement is incorrect about this observation?
(a) The H for the reaction N2O4(g) 2NO2(g) is +ve
(b) Paramagnetism increases on heating
(c) The H-U at 100C is equal to 200 cal
(d) Dimerisation is reduced on heating
Enthalpy of the reaction,
CH4(g) + 1/2 O2(g) CH3OH (l), is negative. If enthalpy of combustion of CH4 and CH3OH are x and y respectively, then which relation is correct?
(a) x>y (b) x<y (c) x=y (d) xy
In the reaction, H and S both are positive. In which of the following cases, the reaction would not be spontaneous?
(a) H>TS (b) S=H/T
(c) H=TS (d) All of these
When an ideal gas is compressed adiabatically and reversibly, the final temperature is:
(a) higher than the initial temperature
(b) lower than the initial temperature
(c) the same as the initial temperature
(d) dependent on the rate of compression
The standard change is Gibbs energy for the reaction,
H2OH+ + OH- at 25C is:
1. 100 kJ 2. -90 kJ
3. 90 kJ 4. -100 kJ