A process among the following shows decrease in entropy is :

1. \(2 \text H \left(g\right)\rightarrow\text H_{2} \left(g\right)\)

2. Evaporation of water

3. Expansion of a gas at a constant temperature

4. Sublimation of solid to gas

Under the isothermal condition, a gas at \(300 \mathrm{~K}\) expands from \(0.1 \mathrm{~L}\) to \(0.25 \mathrm{~L}\) against a constant external pressure of 2 bar. The work done by the gas is:

The enthalpy of combustion of H₂, cyclohexene (C₆H₁₀) and cyclohexane (C₆H₁₂) are -241, -3800 and -3920 kJ per mol respectively. Heat of hydrogenation of cyclohexene is:

1. -121 kJ per mol

2. +121 kJ per mol

3. +242 kJ per mol

4. -242 kJ per mol

The enthalpy and entropy change for the reaction: Br₂ (l) + Cl₂ (g) →2BrCl(g), are 30kJ mol^-1 and 105 JK^-1 mol^-1 respectively. The temperature at which the reaction will be in equilibrium is: 

1. 285.7 K

2. 273 K

3. 450 K

4. 300 K

Assuming each reaction is carried out in an open container,
Reaction that shows ΔH=ΔE is :

1. $H_2\left(g\right)+B{r}_2\left(g\right)\to 2HBr\left(g\right)$

2. $C\left(s\right)+2H_{2}O\left(g\right)\to 2H_2\left(g\right)+C{O}_2\left(g\right)$

3. $PC{l}_5\left(g\right)\to PC{l}_3\left(g\right)+C{l}_2\left(g\right)$

4. $2CO\left(g\right)+O_2\left(g\right)\to 2C{O}_2\left(g\right)$

Identify the correct statement for change of Gibbs energy for a system (ΔG_system) at constant temperature and pressure:

The bond energy of H—H and Cl-Cl is 430 kJ
mol^-1 and 240 kJ mol^-1 respectively and ΔH_f for HCl is -90 kJ mol^-1. The bond enthalpy of HCl is:

1. 290 $kJ$ $mo{l}^{-1}$

2. 380 $kJ$ $mo{l}^{-1}$

3. 425 $kJ$ $mo{l}^{-1}$

4. 245 $kJ$ $mo{l}^{-1}$

Consider the following reactions: 

Enthalpy of formation of H₂O(l) is :

1. $-x_3$ $kJ$ $mo{l}^{-1}$

2. $-x_4$ $kJ$ $mo{l}^{-1}$

3. $-x_1$ $kJ$ $mo{l}^{-1}$

4. $-x_2$ $kJ$ $mo{l}^{-1}$