Thermodynamics

Standard entropies of X2, Y2 and XY5 are 70, 50 and 110 J K-1 mol-1 respectively. The temperature in Kelvin at which the reaction 12X2 + 52Y2 XY5 H = -35 kJ mol-1 will be at equilibrium is (Nearest integer)

S(g)+ 32O2(g) SO3(g)+2x kcal SO2(g)+ 12O2(g) SO3(g)+y kcal The heat of formation of SO2(g) is given by :

1. 2x+y kcal
2. 2xy kcal
3. y-2x kcal
4. x+y kcal

Which of the following mixing of 1 M base and 1 M acid leads to the largest increase in temperature?

1. 50 mL HCl and 20 mL NaOH
2. 30 mL HCl and 30 mL NaOH
3. 45 mL CH3COOH and 25 mL NaOH
4. 30 mL CH3COOH and 30 mL NaOH

Ice at -5 C is heated to become vapor with temperature of 110 C at atmospheric pressure. The entropy change associated with this process can be obtained from

1. 268 K273 K Cp,m dT + Hm, fusionTf + Hm, vaporisationTb + 273 K373 K Cp,m dT + 373 K383 K Cp,m dT
2. 268 K383 K Cp dT + Hmelting273 + Hboiling373
3. 268 K383 K Cp dT + qrevT
4. 268 K273 K Cp,mT dT + Hm, fusionTf + Hm, vaporisationTb + 273 K373 K Cp,m dTT + 373 K383 K Cp,m dTT

The standard enthalpy and standard entropy of decomposition of N2O4 to NO2 are 55.0 kJ mol-1 and 175.0 J/K/mol respectively. The standard free energy change for this reaction at 25 in J mol-1 is (Nearest integer)

The effect of temperature on spontaneity of reactions are represented as : [figure] The incorrect combinations are :

1. A and C only
2. B and D only
3. A and D only
4. B and C only

The bond dissociation enthalpy of X2 H bond calculated from the given data is kJ mol-1. (Nearest integer) M+X-(s) M+(g)+X-(g) H lattice=800 kJ mol-1 M(s) M(g) H sub=100 kJ mol-1 M(g) M+(g)+e-(g) H i=500 kJ mol-1 X(g)+e-(g) X-(g) H eg=-300 kJ mol-1 M(s)+ 12X2(g) M+X-(s) H f=-400 kJ mol-1 [Given : M+X- is a pure ionic compound and X forms a diatomic molecule X2 in gaseous state]

A liquid when kept inside a thermally insulated closed vessel at 25 was mechanically stirred from outside. What will be the correct option for the following thermodynamic parameters ?

1. U = 0, q < 0, w > 0
2. U > 0, q = 0, w > 0
3. U = 0, q = 0, w = 0
4. U < 0, q = 0, w > 0

Match List - I with List - II. Choose the correct answer from the options given below :

1. A-I, B-II, C-IV, D-III
2. A-II, B-III, C-I, D-IV
3. A-II, B-I, C-IV, D-III
4. A-II, B-I, C-III, D-IV

Consider the following cases of standard enthalpy of reaction ( Hr in kJ mol-1) C2H6(g)+ 72O2(g) 2CO2(g)+3H2O(l) H1 =-1550 C(graphite)+O2(g) CO2(g) H2 =-393.5 H2(g)+ 12O2(g) H2O(l) H3 =-286 The magnitude of H f C2H6(g) is kJ mol-1 (Nearest integer).