Heat of hydrogenation of ethene is x₁ and that of benzene is x₂. Hence resonance energy is-

1. $x_1-x_2$

2. $x_1+x_2$

3. $3x_1-x_2$

4. $x_1-3x_2$

$$\begin{gathered} {\mathrm{C}}_2{\mathrm{H}}_6\left(\mathrm{g}\right)+3.5{\mathrm{O}}_2\left(\mathrm{g}\right)\to 2{\mathrm{CO}}_2\left(\mathrm{g}\right)+3{\mathrm{H}}_2\mathrm{O}\left(\mathrm{g}\right) \\ ∆{\mathrm{S}}_{\mathrm{vap}}\left({\mathrm{H}}_2\mathrm{O}, \mathrm{l}\right)={\mathrm{x}}_1 \mathrm{cal} {\mathrm{K}}^{-1}\left(\mathrm{b}.\mathrm{p}. +{\mathrm{T}}_1\right) \\ ∆{\mathrm{H}}_{\mathrm{f}}\left({\mathrm{H}}_2\mathrm{O}, \mathrm{l}\right)={\mathrm{x}}_2; ∆{\mathrm{H}}_{\mathrm{f}}\left({\mathrm{CO}}_2\right)={\mathrm{x}}_3, ∆{\mathrm{H}}_{\mathrm{f}}\left({\mathrm{C}}_2{\mathrm{H}}_6\right)={\mathrm{x}}_4 \\ \mathrm{Hence} ∆\mathrm{H} \mathrm{for} \mathrm{the} \mathrm{reaction} \mathrm{is}- \end{gathered}$$

1. $2x_3+3x_2-x_4$

2. $2x_3+3x_2-x_4+3x_1{T}_1$

3. $2x_3+3x_2-x_4-3x_1{T}_1$

4. $x_1{T}_1+x_2+x_3-x_4$

The bond energies of $\mathrm{C}\equiv \mathrm{C}$, C-H, H-H, and C=C are 198, 98, 103, and 145 kcal respectively.

The enthalpy change of the reaction $\mathrm{HC}\equiv \mathrm{CH}+{\mathrm{H}}_2\to {\mathrm{C}}_2{\mathrm{H}}_4$ would be:

1. 48 kcal

2. 96 kcal

3. -40 kcal

4. -152 kcal

$H_2\left(g\right)+\frac{1}{2}{O}_2\left(g\right)\to H_{2}O\left(l\right)$

B.E. (H-H) = x₁; B.E. (O=O) = x₂ B.E. (O-H) = x₃

Latent heat of vaporization of water liquid into water vapour = x₄, then $∆H_f$(heat of formation of liquid water) is-

1. $x_1+\frac{x_2}{2}-x_3+x_4$

2. $2x_3-x_1-\frac{x_2}{2}-x_4$

3. $x_1+\frac{x_2}{2}-2x_3-x_4$

4. $x_1+\frac{x_2}{2}-2x_3+x_4$

In a process the pressure of a gas is inversely proportional to the square of the volume. If temperature of the gas is increased, then work done on the gas-

1. is positive

2. is negative

3. is zero

4. maybe positive

The enthalpies of formation of CO₂(g) and CO(g) at 298 K are in the ratio 2.57 : 1. For the reaction,

$C{O}_2\left(g\right)+C\left(s\right)\to 2 CO\left(g\right), ∆H=172.5 kJ,$
$∆H_f of CO\left(g\right) is$

1. -150.6 kJ mol^-1

2. -302.63 kJ mol^-1

3. -130.2 kJ mol^-1

4. -141.8 kJ mol^-1

In an adiabatic expansion the product of pressure and volume-

1. decreases

2. increases

3. remains constant

4. first increase then decreases

The molar entropy of the vapourization of acetic acid is\(14.4~ \mathrm{cal}~ \mathrm{K}^{-1} \mathrm{~mol}^{-1}\) at its boiling point ${118}^{\circ }C$. The latent heat of vapourization of acetic acid is-

100 ml of 0.3 M HCl solution is mixed with 100 ml of 0.35 M NaOH solution. The amount of heat liberated is

1. 7.3 kJ

2. 5.71 kJ

3. 10.42 kJ

4. 1.713 kJ

The quantity ${\delta }_q$ i.e. heat absorbed an infinitesimal process is

1. Dependent on the path of transformation

2. Dependent on the thermodynamic state of the system

3. Independent of both

4. An exact differential