RBTS PAPER 3(CHEMISTRY)
3 RBTS PAPER

162658 Enthalpy of combustion of a substance is always :

1 \(>0\)
2 \(\geq 0\)
3 \(\leq 0\)
4 \(<0\).
3 RBTS PAPER

162659 Given that -
\(\begin{aligned}
& 2 \mathrm{C}(\mathrm{s})+2 \mathrm{O} 2(\mathrm{~g}) \rightarrow 2 \mathrm{CO}_2(\mathrm{~g}) ; \Delta \mathrm{H}=-787 \mathrm{~kJ} \\
& \mathrm{H}_2(\mathrm{~g})+\frac{1}{2} \mathrm{O}_2(\mathrm{~g}) \rightarrow \mathrm{H}_2 \mathrm{O}(\ell) \quad \Delta \mathrm{H}=-286 \mathrm{~kJ} \\
& \mathrm{C}_2 \mathrm{H}_2(\mathrm{~g})+\frac{5}{2} \mathrm{O}_2(\mathrm{~g}) \rightarrow 2 \mathrm{CO}_2(\mathrm{~g})+\mathrm{H}_2 \mathrm{O}(\mathrm{l}) ; \Delta \mathrm{H}=-1310 \mathrm{~kJ}
\end{aligned}\)
Heat of formation of acetylene is :

1 \(+1802 \mathrm{~kJ}\)
2 \(-1802 \mathrm{~kJ}\)
3 \(-800 \mathrm{~kJ}\)
4 \(+237 \mathrm{~kJ}\)
3 RBTS PAPER

162660 For vaporization of water at 1 atmospheric pressure, the values of \(\Delta \mathrm{H}\) and \(\Delta \mathrm{S}\) are \(40.63 \mathrm{~kJ}\) \(\mathrm{mol}^{-1}\) and \(108.8 \mathrm{JK}^{-1} \mathrm{~mol}^{-1}\), respectively. The temperature when Gibbs energy change \((\Delta \mathbf{G})\) for this transformation will be zero, is :

1 \(393.4 \mathrm{~K}\)
2 \(373.4 \mathrm{~K}\)
3 \(293.4 \mathrm{~K}\)
4 \(273.4 \mathrm{~K}\)
3 RBTS PAPER

162661 Standard entropies of \(X_2, Y_2\) and \(X Y_3\) are 60, 40 and \(50 \mathrm{JK}^{-1} \mathrm{~mol}^{-1}\) respectively. For the reaction the temperature should be :

1 \(500 \mathrm{~K}\)
2 \(750 \mathrm{~K}\)
3 \(1000 \mathrm{~K}\)
4 \(1250 \mathrm{~K}\)
3 RBTS PAPER

162662 If the enthalpy change for the transition of liquid water to steam is \(30 \mathrm{~kJ} \mathrm{~mol}^{-1}\) at \(27^{\circ} \mathrm{C}\), the entropy changes for the process would be:

1 \(10 \mathrm{~J} \mathrm{~mol}^{-} \mathrm{K}^{-1}\)
2 \(1.0 \mathrm{~J} \mathrm{~mol}^{-} \mathrm{K}^{-1}\)
3 \(0.1 \mathrm{~J} \mathrm{~mol}^{-} \mathrm{K}^{-1}\)
4 \(100 \mathrm{~J} \mathrm{~mol}^{-} \mathrm{K}^{-1}\)
3 RBTS PAPER

162658 Enthalpy of combustion of a substance is always :

1 \(>0\)
2 \(\geq 0\)
3 \(\leq 0\)
4 \(<0\).
3 RBTS PAPER

162659 Given that -
\(\begin{aligned}
& 2 \mathrm{C}(\mathrm{s})+2 \mathrm{O} 2(\mathrm{~g}) \rightarrow 2 \mathrm{CO}_2(\mathrm{~g}) ; \Delta \mathrm{H}=-787 \mathrm{~kJ} \\
& \mathrm{H}_2(\mathrm{~g})+\frac{1}{2} \mathrm{O}_2(\mathrm{~g}) \rightarrow \mathrm{H}_2 \mathrm{O}(\ell) \quad \Delta \mathrm{H}=-286 \mathrm{~kJ} \\
& \mathrm{C}_2 \mathrm{H}_2(\mathrm{~g})+\frac{5}{2} \mathrm{O}_2(\mathrm{~g}) \rightarrow 2 \mathrm{CO}_2(\mathrm{~g})+\mathrm{H}_2 \mathrm{O}(\mathrm{l}) ; \Delta \mathrm{H}=-1310 \mathrm{~kJ}
\end{aligned}\)
Heat of formation of acetylene is :

1 \(+1802 \mathrm{~kJ}\)
2 \(-1802 \mathrm{~kJ}\)
3 \(-800 \mathrm{~kJ}\)
4 \(+237 \mathrm{~kJ}\)
3 RBTS PAPER

162660 For vaporization of water at 1 atmospheric pressure, the values of \(\Delta \mathrm{H}\) and \(\Delta \mathrm{S}\) are \(40.63 \mathrm{~kJ}\) \(\mathrm{mol}^{-1}\) and \(108.8 \mathrm{JK}^{-1} \mathrm{~mol}^{-1}\), respectively. The temperature when Gibbs energy change \((\Delta \mathbf{G})\) for this transformation will be zero, is :

1 \(393.4 \mathrm{~K}\)
2 \(373.4 \mathrm{~K}\)
3 \(293.4 \mathrm{~K}\)
4 \(273.4 \mathrm{~K}\)
3 RBTS PAPER

162661 Standard entropies of \(X_2, Y_2\) and \(X Y_3\) are 60, 40 and \(50 \mathrm{JK}^{-1} \mathrm{~mol}^{-1}\) respectively. For the reaction the temperature should be :

1 \(500 \mathrm{~K}\)
2 \(750 \mathrm{~K}\)
3 \(1000 \mathrm{~K}\)
4 \(1250 \mathrm{~K}\)
3 RBTS PAPER

162662 If the enthalpy change for the transition of liquid water to steam is \(30 \mathrm{~kJ} \mathrm{~mol}^{-1}\) at \(27^{\circ} \mathrm{C}\), the entropy changes for the process would be:

1 \(10 \mathrm{~J} \mathrm{~mol}^{-} \mathrm{K}^{-1}\)
2 \(1.0 \mathrm{~J} \mathrm{~mol}^{-} \mathrm{K}^{-1}\)
3 \(0.1 \mathrm{~J} \mathrm{~mol}^{-} \mathrm{K}^{-1}\)
4 \(100 \mathrm{~J} \mathrm{~mol}^{-} \mathrm{K}^{-1}\)
3 RBTS PAPER

162658 Enthalpy of combustion of a substance is always :

1 \(>0\)
2 \(\geq 0\)
3 \(\leq 0\)
4 \(<0\).
3 RBTS PAPER

162659 Given that -
\(\begin{aligned}
& 2 \mathrm{C}(\mathrm{s})+2 \mathrm{O} 2(\mathrm{~g}) \rightarrow 2 \mathrm{CO}_2(\mathrm{~g}) ; \Delta \mathrm{H}=-787 \mathrm{~kJ} \\
& \mathrm{H}_2(\mathrm{~g})+\frac{1}{2} \mathrm{O}_2(\mathrm{~g}) \rightarrow \mathrm{H}_2 \mathrm{O}(\ell) \quad \Delta \mathrm{H}=-286 \mathrm{~kJ} \\
& \mathrm{C}_2 \mathrm{H}_2(\mathrm{~g})+\frac{5}{2} \mathrm{O}_2(\mathrm{~g}) \rightarrow 2 \mathrm{CO}_2(\mathrm{~g})+\mathrm{H}_2 \mathrm{O}(\mathrm{l}) ; \Delta \mathrm{H}=-1310 \mathrm{~kJ}
\end{aligned}\)
Heat of formation of acetylene is :

1 \(+1802 \mathrm{~kJ}\)
2 \(-1802 \mathrm{~kJ}\)
3 \(-800 \mathrm{~kJ}\)
4 \(+237 \mathrm{~kJ}\)
3 RBTS PAPER

162660 For vaporization of water at 1 atmospheric pressure, the values of \(\Delta \mathrm{H}\) and \(\Delta \mathrm{S}\) are \(40.63 \mathrm{~kJ}\) \(\mathrm{mol}^{-1}\) and \(108.8 \mathrm{JK}^{-1} \mathrm{~mol}^{-1}\), respectively. The temperature when Gibbs energy change \((\Delta \mathbf{G})\) for this transformation will be zero, is :

1 \(393.4 \mathrm{~K}\)
2 \(373.4 \mathrm{~K}\)
3 \(293.4 \mathrm{~K}\)
4 \(273.4 \mathrm{~K}\)
3 RBTS PAPER

162661 Standard entropies of \(X_2, Y_2\) and \(X Y_3\) are 60, 40 and \(50 \mathrm{JK}^{-1} \mathrm{~mol}^{-1}\) respectively. For the reaction the temperature should be :

1 \(500 \mathrm{~K}\)
2 \(750 \mathrm{~K}\)
3 \(1000 \mathrm{~K}\)
4 \(1250 \mathrm{~K}\)
3 RBTS PAPER

162662 If the enthalpy change for the transition of liquid water to steam is \(30 \mathrm{~kJ} \mathrm{~mol}^{-1}\) at \(27^{\circ} \mathrm{C}\), the entropy changes for the process would be:

1 \(10 \mathrm{~J} \mathrm{~mol}^{-} \mathrm{K}^{-1}\)
2 \(1.0 \mathrm{~J} \mathrm{~mol}^{-} \mathrm{K}^{-1}\)
3 \(0.1 \mathrm{~J} \mathrm{~mol}^{-} \mathrm{K}^{-1}\)
4 \(100 \mathrm{~J} \mathrm{~mol}^{-} \mathrm{K}^{-1}\)
3 RBTS PAPER

162658 Enthalpy of combustion of a substance is always :

1 \(>0\)
2 \(\geq 0\)
3 \(\leq 0\)
4 \(<0\).
3 RBTS PAPER

162659 Given that -
\(\begin{aligned}
& 2 \mathrm{C}(\mathrm{s})+2 \mathrm{O} 2(\mathrm{~g}) \rightarrow 2 \mathrm{CO}_2(\mathrm{~g}) ; \Delta \mathrm{H}=-787 \mathrm{~kJ} \\
& \mathrm{H}_2(\mathrm{~g})+\frac{1}{2} \mathrm{O}_2(\mathrm{~g}) \rightarrow \mathrm{H}_2 \mathrm{O}(\ell) \quad \Delta \mathrm{H}=-286 \mathrm{~kJ} \\
& \mathrm{C}_2 \mathrm{H}_2(\mathrm{~g})+\frac{5}{2} \mathrm{O}_2(\mathrm{~g}) \rightarrow 2 \mathrm{CO}_2(\mathrm{~g})+\mathrm{H}_2 \mathrm{O}(\mathrm{l}) ; \Delta \mathrm{H}=-1310 \mathrm{~kJ}
\end{aligned}\)
Heat of formation of acetylene is :

1 \(+1802 \mathrm{~kJ}\)
2 \(-1802 \mathrm{~kJ}\)
3 \(-800 \mathrm{~kJ}\)
4 \(+237 \mathrm{~kJ}\)
3 RBTS PAPER

162660 For vaporization of water at 1 atmospheric pressure, the values of \(\Delta \mathrm{H}\) and \(\Delta \mathrm{S}\) are \(40.63 \mathrm{~kJ}\) \(\mathrm{mol}^{-1}\) and \(108.8 \mathrm{JK}^{-1} \mathrm{~mol}^{-1}\), respectively. The temperature when Gibbs energy change \((\Delta \mathbf{G})\) for this transformation will be zero, is :

1 \(393.4 \mathrm{~K}\)
2 \(373.4 \mathrm{~K}\)
3 \(293.4 \mathrm{~K}\)
4 \(273.4 \mathrm{~K}\)
3 RBTS PAPER

162661 Standard entropies of \(X_2, Y_2\) and \(X Y_3\) are 60, 40 and \(50 \mathrm{JK}^{-1} \mathrm{~mol}^{-1}\) respectively. For the reaction the temperature should be :

1 \(500 \mathrm{~K}\)
2 \(750 \mathrm{~K}\)
3 \(1000 \mathrm{~K}\)
4 \(1250 \mathrm{~K}\)
3 RBTS PAPER

162662 If the enthalpy change for the transition of liquid water to steam is \(30 \mathrm{~kJ} \mathrm{~mol}^{-1}\) at \(27^{\circ} \mathrm{C}\), the entropy changes for the process would be:

1 \(10 \mathrm{~J} \mathrm{~mol}^{-} \mathrm{K}^{-1}\)
2 \(1.0 \mathrm{~J} \mathrm{~mol}^{-} \mathrm{K}^{-1}\)
3 \(0.1 \mathrm{~J} \mathrm{~mol}^{-} \mathrm{K}^{-1}\)
4 \(100 \mathrm{~J} \mathrm{~mol}^{-} \mathrm{K}^{-1}\)
3 RBTS PAPER

162658 Enthalpy of combustion of a substance is always :

1 \(>0\)
2 \(\geq 0\)
3 \(\leq 0\)
4 \(<0\).
3 RBTS PAPER

162659 Given that -
\(\begin{aligned}
& 2 \mathrm{C}(\mathrm{s})+2 \mathrm{O} 2(\mathrm{~g}) \rightarrow 2 \mathrm{CO}_2(\mathrm{~g}) ; \Delta \mathrm{H}=-787 \mathrm{~kJ} \\
& \mathrm{H}_2(\mathrm{~g})+\frac{1}{2} \mathrm{O}_2(\mathrm{~g}) \rightarrow \mathrm{H}_2 \mathrm{O}(\ell) \quad \Delta \mathrm{H}=-286 \mathrm{~kJ} \\
& \mathrm{C}_2 \mathrm{H}_2(\mathrm{~g})+\frac{5}{2} \mathrm{O}_2(\mathrm{~g}) \rightarrow 2 \mathrm{CO}_2(\mathrm{~g})+\mathrm{H}_2 \mathrm{O}(\mathrm{l}) ; \Delta \mathrm{H}=-1310 \mathrm{~kJ}
\end{aligned}\)
Heat of formation of acetylene is :

1 \(+1802 \mathrm{~kJ}\)
2 \(-1802 \mathrm{~kJ}\)
3 \(-800 \mathrm{~kJ}\)
4 \(+237 \mathrm{~kJ}\)
3 RBTS PAPER

162660 For vaporization of water at 1 atmospheric pressure, the values of \(\Delta \mathrm{H}\) and \(\Delta \mathrm{S}\) are \(40.63 \mathrm{~kJ}\) \(\mathrm{mol}^{-1}\) and \(108.8 \mathrm{JK}^{-1} \mathrm{~mol}^{-1}\), respectively. The temperature when Gibbs energy change \((\Delta \mathbf{G})\) for this transformation will be zero, is :

1 \(393.4 \mathrm{~K}\)
2 \(373.4 \mathrm{~K}\)
3 \(293.4 \mathrm{~K}\)
4 \(273.4 \mathrm{~K}\)
3 RBTS PAPER

162661 Standard entropies of \(X_2, Y_2\) and \(X Y_3\) are 60, 40 and \(50 \mathrm{JK}^{-1} \mathrm{~mol}^{-1}\) respectively. For the reaction the temperature should be :

1 \(500 \mathrm{~K}\)
2 \(750 \mathrm{~K}\)
3 \(1000 \mathrm{~K}\)
4 \(1250 \mathrm{~K}\)
3 RBTS PAPER

162662 If the enthalpy change for the transition of liquid water to steam is \(30 \mathrm{~kJ} \mathrm{~mol}^{-1}\) at \(27^{\circ} \mathrm{C}\), the entropy changes for the process would be:

1 \(10 \mathrm{~J} \mathrm{~mol}^{-} \mathrm{K}^{-1}\)
2 \(1.0 \mathrm{~J} \mathrm{~mol}^{-} \mathrm{K}^{-1}\)
3 \(0.1 \mathrm{~J} \mathrm{~mol}^{-} \mathrm{K}^{-1}\)
4 \(100 \mathrm{~J} \mathrm{~mol}^{-} \mathrm{K}^{-1}\)