05. Gibbs Energy Change and Equilibrium
Thermodynamics

273076 The correct relationship between free energy change in a reaction and the corresponding equilibrium constant $K_c$ is

1 $\Delta \mathrm{G}=\mathrm{RT} \ln \mathrm{K}_{\mathrm{c}}$
2 $-\Delta \mathrm{G}=\mathrm{RT} 1 \mathrm{nK}_{\mathrm{c}}$
3 $\Delta \mathrm{G}^{\circ}=\mathrm{RT} 1 \mathrm{nK}_{\mathrm{c}}$
4 $-\Delta \mathrm{G}^{\circ}=$ RT $1 \mathrm{nK}_{\mathrm{c}}$
Thermodynamics

273077 In a fuel cell, methanol is used as fuel and oxygen gas is used as an oxidiser. The reaction is
$\mathrm{CH}_3 \mathrm{OH}(l)+\frac{3}{2} \mathrm{O}_2(\mathrm{~g}) \longrightarrow \mathrm{CO}_2(\mathrm{~g})+2 \mathrm{H}_2 \mathrm{O}(l)$
At $298 \mathrm{~K}$ standard Gibb's energies of formation for $\mathrm{CH}_3 \mathrm{OH}(l), \mathrm{H}_2 \mathrm{O}(l)$ and $\mathrm{CO}_2$ (g) are $-166.2,-237.2$ and $-394.4 \mathrm{~kJ} \mathrm{~mol}^{-1}$, respectively. If standard enthalpy of combustion of methanol is $-726 \mathrm{~kJ} \mathrm{~mol}^{-1}$, efficiency of the fuel cell will be

1 $90 \%$
2 $80 \%$
3 $87 \%$
4 $97 \%$
Thermodynamics

273079 The standard reaction Gibbs energy for a chemical reaction at an absolute temperature $T$ is given by,
$\Delta_{\mathrm{r}} \mathbf{G}^{\circ}=\mathbf{A}-\mathbf{B T}$
Where $A$ and $B$ are non-zero constants.
Which of the following is true about this reaction?

1 Endothermic if, $\mathrm{A}<0$ and $\mathrm{B}>0$
2 Exothermic if, $\mathrm{B}<0$
3 Exothermic if, $\mathrm{A}>0$ and $\mathrm{B}<0$
4 Endothermic if, $\mathrm{A}>0$
Thermodynamics

273086 Which of the following can help predict the rate of a reaction if the standard Gibbs free energy of reaction $(\Delta G)$ is known?

1 Equilibrium constant
2 $\Delta \mathrm{H}$
3 $\Delta \mathrm{U}$
4 Heat liberated during the course of reaction in calorimeter
5 Both (a) and (b)
Thermodynamics

273089 Enthalpy of hydrogenation of one mole of benzene to cyclohexane is [Resonance energy of benzene $=-150.4 \mathrm{~kJ} /$ mole.
Enthalpy of hydrogenation of cyclohexene =$119.5 \mathrm{~kJ} / \mathrm{mole}]$

1 $-208.1 \mathrm{~kJ} / \mathrm{mole}$
2 $-358.1 \mathrm{~kJ} / \mathrm{mole}$
3 $+150.4 \mathrm{~kJ} / \mathrm{mole}$
4 $-269.9 \mathrm{~kJ} / \mathrm{mole}$
Thermodynamics

273076 The correct relationship between free energy change in a reaction and the corresponding equilibrium constant $K_c$ is

1 $\Delta \mathrm{G}=\mathrm{RT} \ln \mathrm{K}_{\mathrm{c}}$
2 $-\Delta \mathrm{G}=\mathrm{RT} 1 \mathrm{nK}_{\mathrm{c}}$
3 $\Delta \mathrm{G}^{\circ}=\mathrm{RT} 1 \mathrm{nK}_{\mathrm{c}}$
4 $-\Delta \mathrm{G}^{\circ}=$ RT $1 \mathrm{nK}_{\mathrm{c}}$
Thermodynamics

273077 In a fuel cell, methanol is used as fuel and oxygen gas is used as an oxidiser. The reaction is
$\mathrm{CH}_3 \mathrm{OH}(l)+\frac{3}{2} \mathrm{O}_2(\mathrm{~g}) \longrightarrow \mathrm{CO}_2(\mathrm{~g})+2 \mathrm{H}_2 \mathrm{O}(l)$
At $298 \mathrm{~K}$ standard Gibb's energies of formation for $\mathrm{CH}_3 \mathrm{OH}(l), \mathrm{H}_2 \mathrm{O}(l)$ and $\mathrm{CO}_2$ (g) are $-166.2,-237.2$ and $-394.4 \mathrm{~kJ} \mathrm{~mol}^{-1}$, respectively. If standard enthalpy of combustion of methanol is $-726 \mathrm{~kJ} \mathrm{~mol}^{-1}$, efficiency of the fuel cell will be

1 $90 \%$
2 $80 \%$
3 $87 \%$
4 $97 \%$
Thermodynamics

273079 The standard reaction Gibbs energy for a chemical reaction at an absolute temperature $T$ is given by,
$\Delta_{\mathrm{r}} \mathbf{G}^{\circ}=\mathbf{A}-\mathbf{B T}$
Where $A$ and $B$ are non-zero constants.
Which of the following is true about this reaction?

1 Endothermic if, $\mathrm{A}<0$ and $\mathrm{B}>0$
2 Exothermic if, $\mathrm{B}<0$
3 Exothermic if, $\mathrm{A}>0$ and $\mathrm{B}<0$
4 Endothermic if, $\mathrm{A}>0$
Thermodynamics

273086 Which of the following can help predict the rate of a reaction if the standard Gibbs free energy of reaction $(\Delta G)$ is known?

1 Equilibrium constant
2 $\Delta \mathrm{H}$
3 $\Delta \mathrm{U}$
4 Heat liberated during the course of reaction in calorimeter
5 Both (a) and (b)
Thermodynamics

273089 Enthalpy of hydrogenation of one mole of benzene to cyclohexane is [Resonance energy of benzene $=-150.4 \mathrm{~kJ} /$ mole.
Enthalpy of hydrogenation of cyclohexene =$119.5 \mathrm{~kJ} / \mathrm{mole}]$

1 $-208.1 \mathrm{~kJ} / \mathrm{mole}$
2 $-358.1 \mathrm{~kJ} / \mathrm{mole}$
3 $+150.4 \mathrm{~kJ} / \mathrm{mole}$
4 $-269.9 \mathrm{~kJ} / \mathrm{mole}$
Thermodynamics

273076 The correct relationship between free energy change in a reaction and the corresponding equilibrium constant $K_c$ is

1 $\Delta \mathrm{G}=\mathrm{RT} \ln \mathrm{K}_{\mathrm{c}}$
2 $-\Delta \mathrm{G}=\mathrm{RT} 1 \mathrm{nK}_{\mathrm{c}}$
3 $\Delta \mathrm{G}^{\circ}=\mathrm{RT} 1 \mathrm{nK}_{\mathrm{c}}$
4 $-\Delta \mathrm{G}^{\circ}=$ RT $1 \mathrm{nK}_{\mathrm{c}}$
Thermodynamics

273077 In a fuel cell, methanol is used as fuel and oxygen gas is used as an oxidiser. The reaction is
$\mathrm{CH}_3 \mathrm{OH}(l)+\frac{3}{2} \mathrm{O}_2(\mathrm{~g}) \longrightarrow \mathrm{CO}_2(\mathrm{~g})+2 \mathrm{H}_2 \mathrm{O}(l)$
At $298 \mathrm{~K}$ standard Gibb's energies of formation for $\mathrm{CH}_3 \mathrm{OH}(l), \mathrm{H}_2 \mathrm{O}(l)$ and $\mathrm{CO}_2$ (g) are $-166.2,-237.2$ and $-394.4 \mathrm{~kJ} \mathrm{~mol}^{-1}$, respectively. If standard enthalpy of combustion of methanol is $-726 \mathrm{~kJ} \mathrm{~mol}^{-1}$, efficiency of the fuel cell will be

1 $90 \%$
2 $80 \%$
3 $87 \%$
4 $97 \%$
Thermodynamics

273079 The standard reaction Gibbs energy for a chemical reaction at an absolute temperature $T$ is given by,
$\Delta_{\mathrm{r}} \mathbf{G}^{\circ}=\mathbf{A}-\mathbf{B T}$
Where $A$ and $B$ are non-zero constants.
Which of the following is true about this reaction?

1 Endothermic if, $\mathrm{A}<0$ and $\mathrm{B}>0$
2 Exothermic if, $\mathrm{B}<0$
3 Exothermic if, $\mathrm{A}>0$ and $\mathrm{B}<0$
4 Endothermic if, $\mathrm{A}>0$
Thermodynamics

273086 Which of the following can help predict the rate of a reaction if the standard Gibbs free energy of reaction $(\Delta G)$ is known?

1 Equilibrium constant
2 $\Delta \mathrm{H}$
3 $\Delta \mathrm{U}$
4 Heat liberated during the course of reaction in calorimeter
5 Both (a) and (b)
Thermodynamics

273089 Enthalpy of hydrogenation of one mole of benzene to cyclohexane is [Resonance energy of benzene $=-150.4 \mathrm{~kJ} /$ mole.
Enthalpy of hydrogenation of cyclohexene =$119.5 \mathrm{~kJ} / \mathrm{mole}]$

1 $-208.1 \mathrm{~kJ} / \mathrm{mole}$
2 $-358.1 \mathrm{~kJ} / \mathrm{mole}$
3 $+150.4 \mathrm{~kJ} / \mathrm{mole}$
4 $-269.9 \mathrm{~kJ} / \mathrm{mole}$
Thermodynamics

273076 The correct relationship between free energy change in a reaction and the corresponding equilibrium constant $K_c$ is

1 $\Delta \mathrm{G}=\mathrm{RT} \ln \mathrm{K}_{\mathrm{c}}$
2 $-\Delta \mathrm{G}=\mathrm{RT} 1 \mathrm{nK}_{\mathrm{c}}$
3 $\Delta \mathrm{G}^{\circ}=\mathrm{RT} 1 \mathrm{nK}_{\mathrm{c}}$
4 $-\Delta \mathrm{G}^{\circ}=$ RT $1 \mathrm{nK}_{\mathrm{c}}$
Thermodynamics

273077 In a fuel cell, methanol is used as fuel and oxygen gas is used as an oxidiser. The reaction is
$\mathrm{CH}_3 \mathrm{OH}(l)+\frac{3}{2} \mathrm{O}_2(\mathrm{~g}) \longrightarrow \mathrm{CO}_2(\mathrm{~g})+2 \mathrm{H}_2 \mathrm{O}(l)$
At $298 \mathrm{~K}$ standard Gibb's energies of formation for $\mathrm{CH}_3 \mathrm{OH}(l), \mathrm{H}_2 \mathrm{O}(l)$ and $\mathrm{CO}_2$ (g) are $-166.2,-237.2$ and $-394.4 \mathrm{~kJ} \mathrm{~mol}^{-1}$, respectively. If standard enthalpy of combustion of methanol is $-726 \mathrm{~kJ} \mathrm{~mol}^{-1}$, efficiency of the fuel cell will be

1 $90 \%$
2 $80 \%$
3 $87 \%$
4 $97 \%$
Thermodynamics

273079 The standard reaction Gibbs energy for a chemical reaction at an absolute temperature $T$ is given by,
$\Delta_{\mathrm{r}} \mathbf{G}^{\circ}=\mathbf{A}-\mathbf{B T}$
Where $A$ and $B$ are non-zero constants.
Which of the following is true about this reaction?

1 Endothermic if, $\mathrm{A}<0$ and $\mathrm{B}>0$
2 Exothermic if, $\mathrm{B}<0$
3 Exothermic if, $\mathrm{A}>0$ and $\mathrm{B}<0$
4 Endothermic if, $\mathrm{A}>0$
Thermodynamics

273086 Which of the following can help predict the rate of a reaction if the standard Gibbs free energy of reaction $(\Delta G)$ is known?

1 Equilibrium constant
2 $\Delta \mathrm{H}$
3 $\Delta \mathrm{U}$
4 Heat liberated during the course of reaction in calorimeter
5 Both (a) and (b)
Thermodynamics

273089 Enthalpy of hydrogenation of one mole of benzene to cyclohexane is [Resonance energy of benzene $=-150.4 \mathrm{~kJ} /$ mole.
Enthalpy of hydrogenation of cyclohexene =$119.5 \mathrm{~kJ} / \mathrm{mole}]$

1 $-208.1 \mathrm{~kJ} / \mathrm{mole}$
2 $-358.1 \mathrm{~kJ} / \mathrm{mole}$
3 $+150.4 \mathrm{~kJ} / \mathrm{mole}$
4 $-269.9 \mathrm{~kJ} / \mathrm{mole}$
Thermodynamics

273076 The correct relationship between free energy change in a reaction and the corresponding equilibrium constant $K_c$ is

1 $\Delta \mathrm{G}=\mathrm{RT} \ln \mathrm{K}_{\mathrm{c}}$
2 $-\Delta \mathrm{G}=\mathrm{RT} 1 \mathrm{nK}_{\mathrm{c}}$
3 $\Delta \mathrm{G}^{\circ}=\mathrm{RT} 1 \mathrm{nK}_{\mathrm{c}}$
4 $-\Delta \mathrm{G}^{\circ}=$ RT $1 \mathrm{nK}_{\mathrm{c}}$
Thermodynamics

273077 In a fuel cell, methanol is used as fuel and oxygen gas is used as an oxidiser. The reaction is
$\mathrm{CH}_3 \mathrm{OH}(l)+\frac{3}{2} \mathrm{O}_2(\mathrm{~g}) \longrightarrow \mathrm{CO}_2(\mathrm{~g})+2 \mathrm{H}_2 \mathrm{O}(l)$
At $298 \mathrm{~K}$ standard Gibb's energies of formation for $\mathrm{CH}_3 \mathrm{OH}(l), \mathrm{H}_2 \mathrm{O}(l)$ and $\mathrm{CO}_2$ (g) are $-166.2,-237.2$ and $-394.4 \mathrm{~kJ} \mathrm{~mol}^{-1}$, respectively. If standard enthalpy of combustion of methanol is $-726 \mathrm{~kJ} \mathrm{~mol}^{-1}$, efficiency of the fuel cell will be

1 $90 \%$
2 $80 \%$
3 $87 \%$
4 $97 \%$
Thermodynamics

273079 The standard reaction Gibbs energy for a chemical reaction at an absolute temperature $T$ is given by,
$\Delta_{\mathrm{r}} \mathbf{G}^{\circ}=\mathbf{A}-\mathbf{B T}$
Where $A$ and $B$ are non-zero constants.
Which of the following is true about this reaction?

1 Endothermic if, $\mathrm{A}<0$ and $\mathrm{B}>0$
2 Exothermic if, $\mathrm{B}<0$
3 Exothermic if, $\mathrm{A}>0$ and $\mathrm{B}<0$
4 Endothermic if, $\mathrm{A}>0$
Thermodynamics

273086 Which of the following can help predict the rate of a reaction if the standard Gibbs free energy of reaction $(\Delta G)$ is known?

1 Equilibrium constant
2 $\Delta \mathrm{H}$
3 $\Delta \mathrm{U}$
4 Heat liberated during the course of reaction in calorimeter
5 Both (a) and (b)
Thermodynamics

273089 Enthalpy of hydrogenation of one mole of benzene to cyclohexane is [Resonance energy of benzene $=-150.4 \mathrm{~kJ} /$ mole.
Enthalpy of hydrogenation of cyclohexene =$119.5 \mathrm{~kJ} / \mathrm{mole}]$

1 $-208.1 \mathrm{~kJ} / \mathrm{mole}$
2 $-358.1 \mathrm{~kJ} / \mathrm{mole}$
3 $+150.4 \mathrm{~kJ} / \mathrm{mole}$
4 $-269.9 \mathrm{~kJ} / \mathrm{mole}$