Which of the following is the enthalpy change for the hydrogenation of ethyne to ethene?

HC≡CH + H₂ → C₂H₄
Given bond energies: 
C≡C = 198 kcal mol⁻¹
C–H = 98 kcal mol⁻¹
H–H = 103 kcal mol⁻¹
C=C = 145 kcal mol⁻¹

1. 48 kcal

2. 96 kcal

3. -40 kcal

4. -152 kcal

Which among the following state functions is an extensive property of the system?

For the reaction, $2{\mathrm{N}}_2\left(\mathrm{g}\right)+{\mathrm{O}}_2\left(\mathrm{g}\right)\to 2{\mathrm{N}}_2\mathrm{O}\left(\mathrm{g}\right)$, at 298K $∆\mathrm{H}$ is 164 kJ mol^-1. The $∆\mathrm{E}$ of the reaction is :
1. \(166.5 \mathrm{~kJ} \mathrm{~mol}^{-1} \)
2. \(141.5 \mathrm{~kJ} \mathrm{~mol}^{-1} \)
3. \(104.0 \mathrm{~kJ} \mathrm{~mol}^{-1} \)
4. \(-169 \mathrm{~kJ} \mathrm{~mol}^{-1}\)

In an isothermal change, an ideal gas obeys:

For a sample of a perfect gas when its pressure is changed isothermally from P_i to P_f, the entropy change is given by:

1. $∆\mathrm{s}=\mathrm{nR}$ $\ln$ $\left(\frac{{\mathrm{p}}_{\mathrm{f}}}{{\mathrm{p}}_{\mathrm{i}}}\right)$

2. $∆\mathrm{s}=\mathrm{nR}$ $\ln$ $\left(\frac{{\mathrm{p}}_{\mathrm{i}}}{{\mathrm{p}}_{\mathrm{f}}}\right)$

3. $∆\mathrm{s}=\mathrm{nRT}$ $\ln$ $\left(\frac{{\mathrm{p}}_{\mathrm{f}}}{{\mathrm{p}}_{\mathrm{i}}}\right)$

4. $∆\mathrm{s}=\mathrm{RT}$ $\ln$ $\left(\frac{{\mathrm{p}}_{\mathrm{i}}}{{\mathrm{p}}_{\mathrm{f}}}\right)$

For a given reaction, ∆H = 35.5 kJ mol^–1 and ∆S = 83.6 J K^–1 mol^–1. The reaction is spontaneous at:
[Note: Assume that ∆H and ∆S  do not vary with temperature]

1. T > 425K
2. All temperatures
3. T > 298K
4. T < 425K

The bond dissociation energies of X₂ , Y₂ and XY are in the ratio of 1 : 0.5 : 1. ∆H for the formation of XY is –200 kJ mol^–1. The bond dissociation energy of X₂ will be

The heat of combustion of carbon to CO₂ is –393.5 KJ/mol. The heat released upon the formation of 35.2 g of CO₂ from carbon and oxygen gas is:

Which of the following statements is correct for the spontaneous adsorption of a gas?