1. | Carbon and hydrogen act as suitable reducing agents for metal sulphides |
2. | The \(\Delta_f G^0\) of the sulphide is greater than those for \(C S_2\) and \(\mathrm{H}_2 \mathrm{~S}\) |
3. | The \(\Delta_f G^0\) is negative for roasting of sulphur ore to oxide. |
4. | Roasting of the sulphide to the oxide is thermodynamically feasible |
Identify the correct statement for change of Gibbs energy for a system (ΔGsystem) at constant temperature and pressure:
1. | If \(\begin{equation} \Delta G_{\text {system }} \end{equation}\) > 0 , the process is spontaneous |
2. | If \(\begin{equation} \Delta G_{\text {system }} \end{equation}\) = 0 , the system has attained equilibrium |
3. | If \(\begin{equation}
\Delta G_{\text {system }}
\end{equation}\) = 0 , the system is still moving in a particular direction. |
4. | If \(\begin{equation} \Delta G_{\text {system }} \end{equation}\)< 0 , the process is not spontaneous |
Assuming each reaction is carried out in an open container,
Reaction that shows ΔH=ΔE is :
1.
2.
3.
4.
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
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
Under the isothermal condition, a gas at 300 K expands from 0.1 L to 0.25 L against a constant external pressure of 2 bar. The work done by the gas is:
[Given that 1 L bar = 100 J]
1. 30 J
2. –30 J
3. 5 kJ
4. 25 J
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
The bond energy of H—H and Cl-Cl is 430 kJ mol-1 and 240 kJ mol-1 respectively
and ΔHf for HCl is -90 kJ mol-1. The bond enthalpy of HCl is:
1. 290
2. 380
3. 425
4. 245
Consider the following reactions:
(i) | H+(aq) + OH-(aq) → H2O(l) ΔH = -x1 kJmol-1 |
(ii) | H2(g) + 1/2O2(g) → H2O(l) ΔH = -x2 kJmol-1 |
(iii) | CO2(g) + H2(g) → CO (g) + H2O(l) ΔH = -x3 kJmol-1 |
(iv) | C2H2(g) + 5/2O2(g) → 2CO2 + H2O(l) ΔH = -x4 kJmol-1 |
Enthalpy of formation of H2O(l) is :
1.
2.
3.
4.
1. 93 kJ mol-1
2. - 245 kJ mol-1
3. -93 kJ mol-1
4. 245 kJ mol-1