Chapter 6

Which of the following conditions may lead to a nonspontaneous change? (a) \(\Delta \mathrm{H}=-\mathrm{ve} ; \Delta \mathrm{S}=+\mathrm{ve}\) (b) \(\Delta \mathrm{H}=-\mathrm{ve} ; \Delta \mathrm{S}=-\mathrm{ve}\) (c) \(\Delta \mathrm{H}\) and \(\Delta \mathrm{S}\) are both \(+\mathrm{ve}\) (d) \(\Delta \mathrm{H}=+\mathrm{ve} ; \Delta \mathrm{S}=-\mathrm{ve}\)

Which of the following relations are correct? (a) \(\mathrm{H}=\mathrm{G}+\mathrm{TS}\) (b) \(\mathrm{E}=\mathrm{H}+\mathrm{PV}\) (c) \(\Delta \mathrm{E}=\mathrm{q}+\mathrm{W}\) (d) \(\mathrm{q}_{\mathrm{v}}=\mathrm{q}_{\mathrm{p}}-\Delta \mathrm{n}_{(\mathrm{g})} \mathrm{RT}\)

Which of the following is /are true about the isothermal expansion of an ideal gas? (a) \(\Delta \mathrm{U}=0\) (b) \(\Delta \mathrm{T}=0\) (c) \(\mathrm{q}=2.303 \mathrm{nRT} \log _{10}\left(\frac{\mathrm{v}_{1}}{\mathrm{v}_{2}}\right)\) (d) \(\mathrm{q}=0\)

For which of the following reactions, is \(\Delta H\) equal to \(\Delta E ?\) (a) \(\mathrm{H}_{2}(\mathrm{~g})+\mathrm{I}_{2}(\mathrm{~g}) \rightarrow 2 \mathrm{HI}(\mathrm{g})\) (b) \(\mathrm{PCl}_{5}(\mathrm{~g}) \rightarrow \mathrm{PCl}_{3}(\mathrm{~g})+\mathrm{Cl}_{2}(\mathrm{~g})\) (c) \(2 \mathrm{H}_{2} \mathrm{O}_{2}(\mathrm{~g}) \rightarrow 2 \mathrm{H}_{2} \mathrm{O}(\mathrm{g})+\mathrm{O}_{2}(\mathrm{~g})\) (d) \(\mathrm{C}(\mathrm{s})+\mathrm{O}_{2}(\mathrm{~g}) \rightarrow \mathrm{CO}_{2}(\mathrm{~g})\)

For the system at equilibrium which of the following are correct? (a) On increasing the temperature of an endothermic reaction, the equilibrium shifts in forward direction because Q decreases. (b) On increasing the temperature of an endothermic reaction, the concentration in moles per litre of the reactants increases. (c) \(\log \mathrm{K}=\frac{1}{2.303 \mathrm{R}}\left(\Delta \mathrm{S}^{\circ}-\frac{\Delta \mathrm{H}^{\circ}}{\mathrm{T}}\right)\) (d) On increasing the temperature of an endothermic reaction, the equilibrium shifts in forward direction because \(\mathrm{K}\) increases.

Which are the intensive properties? (a) Volume (b) Enthalpy (c) Temperature (d) Refractive index

Which of the following relation is/are incorrect? (a) \(\Delta \mathrm{G}=\Delta \mathrm{H}+\Delta \mathrm{nRT}\) (b) \(\Delta \mathrm{G}=\Delta \mathrm{H}+\mathrm{T} \Delta \mathrm{S}\) (c) \(\Delta \mathrm{G}=\Delta \mathrm{H}+\mathrm{T}[\delta\\{\Delta \mathrm{G}\\} / \delta \mathrm{T}]_{\mathrm{P}}\) (d) \(\Delta \mathrm{G}=\Delta \mathrm{H}-\mathrm{T} \Delta \mathrm{S}\)

Which of the following conditions are favourable for the feasibility of a reaction? (a) \(\Delta \mathrm{H}=-\mathrm{ve}, \mathrm{T} \Delta \mathrm{S}=+\mathrm{ve}\) (b) \(\Delta \mathrm{H}=-\mathrm{ve}, \mathrm{T} \Delta \mathrm{S}=-\mathrm{ve}, \mathrm{T} \Delta \mathrm{S}<\Delta \mathrm{H}\) (c) \(\Delta \mathrm{H}=+\mathrm{ve}, \mathrm{T} \Delta \mathrm{S}=+\mathrm{ve}, \mathrm{T} \Delta \mathrm{S}<\Delta \mathrm{H}\) (d) \(\Delta \mathrm{H}=+\mathrm{ve}, \mathrm{T} \Delta \mathrm{S}=+\mathrm{ve}, \mathrm{T} \Delta \mathrm{S}>\Delta \mathrm{H}\)

The incorrect statement(s) among the following is/ are (a) For a system undergoing a cyclic change, \(\oint \frac{\mathrm{fq}}{\mathrm{T}}>0\). (b) A real crystal has lower entropy than ideal crystal. (c) Pressure is an extensive property. (d) A reversible process is always dynamic in nature.

Match the following Column-I (a) \(\Delta \mathrm{G}<0\) (b) \(\Delta \mathrm{S}_{\text {Totl }}<0\) (c) \(\Delta S_{\text {total }}=0\) (d) \(\Delta \mathrm{G}=0\) Column-II (p) spontaneous (q) equili brium (r) \(\Delta \mathrm{H}>\mathrm{T} \Delta \mathrm{S}\) (s) \(\Delta \mathrm{H}<\mathrm{T} \Delta \mathrm{S}\) (t) \(\Delta \mathrm{H}=\Delta \mathrm{E}\)

Match the following Column-I (a) Variation of equilibrium constants with temperature (b) \(\Delta \mathrm{H}\) of \(\mathrm{H}-\mathrm{Cl}\) (c) Law of conservation of energy (d) Variation of heat of reaction with temperature Column-II (p) Kirchoff's equation (q) Hess's law (r) Van't Hoff equation (s) \(-57.2 \mathrm{~kJ} /\) equivalent (t) Born Haber cycle

\(15 \mathrm{~mL}\) of gaseous hydrocarbon requires \(45 \mathrm{~mL}\) of oxygen for complete combustion which produces \(30 \mathrm{~mL}\) of \(\mathrm{CO}_{2}\) gas, measured under identical conditions. The formula of the hydrocarbon is \(\mathrm{C}_{\mathrm{x}} \mathrm{H}_{y}\). The ratio \(\underline{\mathrm{y}}\) is \(\mathrm{x}\) _______.

The standard molar enthalpies of formation of cyclohexane \((I)\) and benzene \((l)\) are \(-155 \mathrm{~kJ} \mathrm{~mol}^{-1}\) and \(+49\) \(\mathrm{kJ} \mathrm{mol}^{-1}\) respectively. The standard enthalpy of hydrogenation of cyclohexane \((I)\) at \(25^{\circ} \mathrm{C}-120 \mathrm{~kJ} \mathrm{~mol}^{-1}\). Resonance energy per gram of benzene is approximately _______ kJ.

The enthalpy change involved in oxidation of glucose is \(-2880 \mathrm{~kJ} \mathrm{~mol}^{-1}, 25 \%\) of this energy is available for muscular work. If \(100 \mathrm{~kJ}\) of muscular work is needed to walk one \(\mathrm{km}\), the maximum distance \((\mathrm{km})\) that a person will be able to walk after taking \(150 \mathrm{~g}\) of glucose is _______.

The freezing point of isobutane is \(-160^{\circ} \mathrm{C} . \Delta \mathrm{H}_{\text {(solid } \rightarrow \text { liquid })}\) is \(+4520 \mathrm{~J} \mathrm{~mol}^{-1}\). For this fusion process, entropy change in \(\mathrm{J} \mathrm{mol}^{-1}\) is \(10 \mathrm{y}\). The value of \(\mathrm{y}\) is _______.

The bond energy of an \(\mathrm{O}-\mathrm{H}\) bond is \(109 \mathrm{kcal} \mathrm{mol}^{-1}\). When \(5 \times 10^{-3}\) mole of water is formed, the energy released in kcals is approximately _______.

Heat required to raise the temperature of \(1 \mathrm{~mol}\) of a substance by \(1^{\circ}\) is called (a) specific heat (b) molar heat capacity (c) water equivalent (d) specific gravity

A heat engine absorbs heat \(Q_{1}\) from a source at tem perature \(\mathrm{T}_{1}\) and heat \(\mathrm{Q}_{2}\) from a source at temperature \(\mathrm{T}_{2} .\) Work done is found to be \(\mathrm{J}\left(\mathrm{Q}_{1}+\mathrm{Q}_{2}\right)\). This is in accordance with: (a) first law of thermodynamics (b) second law of thermodynamics (c) joules equivalent law (d) none of these

The correct relationship between free energy change in a reaction and the corresponding equilibrium constant \(\mathrm{K}_{c}\) is (a) \(\Delta \mathrm{G}=\mathrm{RT} \operatorname{In} \mathrm{K}_{\mathrm{c}}\) (b) \(-\Delta \mathrm{G}=\mathrm{RT}\) In \(\mathrm{K}\) (c) \(\Delta \mathrm{G}^{\circ}=\mathrm{RT}\) In \(\mathrm{K}_{\mathrm{c}}\) (d) \(-\Delta \mathrm{G}^{\circ}=\mathrm{RT}\) In \(\mathrm{K}_{c}\)

If at \(298 \mathrm{~K}\) the bond energies of \(\mathrm{C}-\mathrm{H}, \mathrm{C}-\mathrm{C}, \mathrm{C}=\mathrm{C}\) and \(\mathrm{H}-\mathrm{H}\) bonds are respectively \(414,347,615\) and \(435 \mathrm{~kJ} \mathrm{~mol}^{-1}\), the value of enthalpy change for the reaction \(\mathrm{H}_{2} \mathrm{C}=\mathrm{CH}_{2}(\mathrm{~g})+\mathrm{H}_{2}(\mathrm{~g}) \longrightarrow \mathrm{H}_{3} \mathrm{C}-\mathrm{CH}_{3}(\mathrm{~g})\) at \(298 \mathrm{~K}\) will be (a) \(+250 \mathrm{~kJ}\) (b) \(-250 \mathrm{~kJ}\) (c) \(+125 \mathrm{~kJ}\) (d) \(-125 \mathrm{~kJ}\)

In an irreversible process taking place at constant \(\mathrm{T}\) and \(\mathrm{P}\) and in which only pressure-volume work is being done, the change in Gibbs free energy \((\mathrm{dG})\) and change in entropy (dS), satisfy the criteria: [2003] (a) \((\mathrm{dS})_{\mathrm{V}, \mathrm{E}}<0,(\mathrm{dG})_{\mathrm{T}, \mathrm{P}}<0\) (b) \((\mathrm{dS})_{\mathrm{V}, \mathrm{E}}>0,(\mathrm{dG})_{\mathrm{T}, \mathrm{P}}<0\) (c) \((\mathrm{dS})_{\mathrm{V}, \mathrm{E}}=0,(\mathrm{dG})_{\mathrm{T}, \mathrm{P}}=0\) (d) \((\mathrm{dS})_{\mathrm{V}, \mathrm{E}}=0,(\mathrm{dG})_{\mathrm{T}, \mathrm{P}}>0\)

The internal energy change when a system goes from state \(\mathrm{A}\) to \(\mathrm{B}\) is \(40 \mathrm{~kJ} / \mathrm{mol}\). If the system goes from \(\mathrm{A}\) to B by a reversible path and returns to state A by an irreversible path what would be the net change in internal energy? (a) \(40 \mathrm{~kJ}\) (b) \(>40 \mathrm{~kJ}\) (c) \(<40 \mathrm{~kJ}\) (d) zero

An ideal gas expands in volume from \(1 \times 10^{-3} \mathrm{~m}^{3}\) to 1 \(\times 10^{-2} \mathrm{~m}^{3}\) at \(300 \mathrm{~K}\) against a constant pressure of \(1 \times\) \(10^{5} \mathrm{Nm}^{-2}\). The work done is (a) \(-900 \mathrm{~kJ}\) (b) \(-900 \mathrm{~J}\) (c) \(270 \mathrm{~kJ}\) (d) \(940 \mathrm{~kJ}\)

The enthalpies of combustion of carbon and carbon monoxide are \(-393.5\) and \(-283 \mathrm{~kJ} \mathrm{~mol}^{-1}\) respectively. The enthalpy of formation of carbon monoxide per mole is (a) \(-676.5 \mathrm{~kJ}\) (b) \(-110.5 \mathrm{~kJ}\) (c) \(110.5 \mathrm{~kJ}\) (d) \(676.5 \mathrm{~kJ}\)

If the bond dissociation energies of \(\mathrm{XY}, \mathrm{X}_{2}\) and \(\mathrm{Y}_{2}\) are in the ratio of \(1: 1: 0.5\) and \(\Delta \mathrm{H}_{\mathrm{f}}\) for the formation of \(\mathrm{XY}\) is \(-200 \mathrm{~kJ} / \mathrm{mole}\). The bond dissociation energy of \(\mathrm{X}_{2}\) will be ? \([\mathbf{2 0 0 5}]\) (a) \(100 \mathrm{~kJ} / \mathrm{mole}\) (b) \(400 \mathrm{~kJ} / \mathrm{mole}\) (c) \(600 \mathrm{~kJ} / \mathrm{mole}\) (d) \(800 \mathrm{~kJ} / \mathrm{mole}\)

Consider the reaction \(\mathrm{N}_{2}+3 \mathrm{H}_{2} \rightleftharpoons 2 \mathrm{NH}_{3}\) carried out at constant temperature and pressure. If \(\Delta \mathrm{H}\) and \(\Delta \mathrm{U}\) are the enthalpy and internal energy changes for the reaction, which of the following expressions is true? (a) \(\Delta \mathrm{H}=0\) (b) \(\Delta \mathrm{H}=\Delta \mathrm{U}\) (c) \(\Delta \mathrm{H}<\Delta \mathrm{U}\) (d) \(\Delta \mathrm{H}>\Delta \mathrm{U}\)

An ideal gas is allowed to expand both reversibly and irreversibly in an isolated system. If \(\mathrm{T}_{\mathrm{i}}\) is the initial temperature and \(\mathrm{T}_{\mathrm{f}}\) is the final temperature, which of the following statements is correct? [2006] (a) \(\left(\mathrm{T}_{\mathrm{f}}\right)_{\text {irrev }}>\left(\mathrm{T}_{\mathrm{i}}\right)_{\mathrm{rev}}\) (b) \(\mathrm{T}_{\mathrm{f}}>\mathrm{T}_{\mathrm{i}}\) for reversible process but \(\mathrm{T}_{\mathrm{f}}=\mathrm{T}_{\mathrm{i}}\) for irreversible process (c) \(\left(\mathrm{T}_{\mathrm{f}}\right)_{\text {irrev }}=\left(\mathrm{T}_{\mathrm{i}}\right)_{\mathrm{rev}}\) (d) \(\mathrm{T}_{\mathrm{f}}=\mathrm{T}_{\mathrm{i}}\) for both reversible and irreversible processes

The enthalpy changes for the following processes are listed below. \(\mathrm{Cl}_{2}(\mathrm{~g})=2 \mathrm{C} 1(\mathrm{~g}) ; 242.3 \mathrm{~kJ} \mathrm{~mol}^{-1}\) \(\mathrm{I}_{2}(\mathrm{~g})=21(\mathrm{~g}) ; 151.0 \mathrm{kJmol}^{-1}\) \(\mathrm{ICl}(\mathrm{g})=\mathrm{I}(\mathrm{g})+\mathrm{Cl}(\mathrm{g}) ; 211.3 \mathrm{~kJ} \mathrm{~mol}^{-1}\) \(\mathrm{I}_{2}(\mathrm{~s})=\mathrm{I}_{2}(\mathrm{~g}) ; 62.76 \mathrm{~kJ} \mathrm{~mol}^{-1}\) Given that the standard states for iodine and chlorine are \(\mathrm{I}_{2}(\mathrm{~s})\) and \(\mathrm{Cl},(\mathrm{g})\), the standard enthalpy of formation for \(\mathrm{ICl}(\mathrm{g})\) is [2006] (a) \(-14.6 \mathrm{~kJ} \mathrm{~mol}^{-1}\) (b) \(-16.8 \mathrm{~kJ} \mathrm{~mol}^{-1}\) (c) \(+16.8 \mathrm{~kJ} \mathrm{~mol}^{-1}\) (d) \(+244.8 \mathrm{~kJ} \mathrm{~mol}^{-1}\)

Asuming that water vapour is an ideal gas, the internal energy change \((\Delta U)\) when 1 mol of water is vapourized at 1 bar pressure and \(100^{\circ} \mathrm{C}\), (Given: Molar enthalpy of vaporization of water at 1 bar and \(373 \mathrm{~K}\) \(=41 \mathrm{~kJ} \mathrm{~mol}^{-1}\) and \(\left.\mathrm{R}=8.3 \mathrm{~J} \mathrm{~mol}^{-1} \mathrm{~K}^{-1}\right)\) will be \(\quad\) [2007] (a) \(3.7904 \mathrm{~kJ} \mathrm{~mol}^{-1}\) (b) \(37.904 \mathrm{~kJ} \mathrm{~mol}^{-1}\) (c) \(41.00 \mathrm{~kJ} \mathrm{~mol}^{-1}\) (d) \(4.100 \mathrm{~kJ} \mathrm{~mol}^{-1}\)

Standard entropy of \(\mathrm{X}_{2}, \mathrm{Y}_{2}\) and \(\mathrm{XY}_{3}\) are 60,40 and 50 \(\mathrm{JK}^{-1} \mathrm{~mol}^{-1}\), respectively. For the reaction, \(1 / 2 \mathrm{X}_{2}+3 / 2 \mathrm{Y}_{2} \longrightarrow \mathrm{XY}_{3}, \Delta \mathrm{H}=-30 \mathrm{~kJ}\), to be at equilibrium, the temperature will be (a) \(1250 \mathrm{~K}\) (b) \(500 \mathrm{~K}\) (c) \(750 \mathrm{~K}\) (d) \(1000 \mathrm{~K}\)

Oxidizing power of chlorine in aqueous solution can be determined by the parameters indicated below: \(1 / 2 \mathrm{Cl}_{2}(\mathrm{~g}) \stackrel{1 / 2 \Delta \mathrm{H}_{\mathrm{Dias}}}{\longrightarrow} \mathrm{Cl}(\mathrm{g}) \stackrel{\Delta_{\mathrm{cg}} \mathrm{H}^{-}}{\longrightarrow}\) \(\mathrm{Cl}^{-}(\mathrm{g}) \quad \stackrel{\Delta_{\mathrm{ln} \mathrm{d}} \mathrm{H}}{\mathrm{H}} \longrightarrow \mathrm{Cl}^{-}(\mathrm{aq})\) The energy involved in the conversion of \(1 / 2 \mathrm{Cl}_{2}(\mathrm{~g})\) to \(\mathrm{Cl}^{-}(\mathrm{g})\) (Using the data, \(\Delta \mathrm{H}_{\mathrm{C}_{2}}=240 \mathrm{~kJ} \mathrm{~mol}^{-1}, \Delta_{\mathrm{cg}} \mathrm{H}-\mathrm{Cl}=\) \(\left.-349 \mathrm{~kJ} \mathrm{~mol}^{-1}, \Delta_{\mathrm{lnd}} \mathrm{H}-\mathrm{Cl}=-381 \mathrm{~kJ} \mathrm{~mol}^{-1}\right)\) will be (a) \(+152 \mathrm{~kJ} \mathrm{~mol}^{-1}\) (b) \(-610 \mathrm{~kJ} \mathrm{~mol}^{-1}\) (c) \(-850 \mathrm{~kJ} \mathrm{~mol}^{-1}\) (d) \(+120 \mathrm{~kJ} \mathrm{~mol}^{-\mathrm{t}}\)

For a particular reversible reaction at temperature \(\mathrm{T}\), \(\Delta \mathrm{H}\) and \(\Delta \mathrm{S}\) were found to be both +ve. If \(\mathrm{T}_{\mathrm{e}}\) is the temperature at equilibrium, the reaction would be spontaneous when (a) \(\mathrm{T}_{n}>\mathrm{T}\) (b) \(\mathrm{T}>\mathrm{T}_{\mathrm{e}}\) (c) \(T_{e}\) is 5 times \(\mathrm{T}\) (d) \(\mathrm{T}=\mathrm{T}_{\mathrm{e}}\)

The entropy change involved in the isothermal reversible expansion of 2 moles of an ideal gas from a volume of \(10 \mathrm{dm}^{3}\) to a volume of \(100 \mathrm{dm}^{3}\) at \(27^{\circ} \mathrm{C}\) is: (a) \(35.3 \mathrm{~J} \mathrm{~mol}^{-1} \mathrm{~K}^{-1}\) (b) \(38.3 \mathrm{~J} \mathrm{~mol}^{-1} \mathrm{~K}^{-1}\) (c) \(45.3 \mathrm{~J} \mathrm{~mol}^{-1} \mathrm{~K}^{-1}\) (d) \(23.3 \mathrm{~J} \mathrm{~mol}^{-1} \mathrm{~K}^{-1}\)

The incorrect expression among the following is (a) \(\ln \mathrm{K}=\frac{\Delta \mathrm{H}^{\circ}-\mathrm{T} \Delta \mathrm{S}^{\circ}}{\mathrm{RT}}\) (b) In isothermal process \(\mathrm{W}_{\text {reverible }}=-\mathrm{nRT} \operatorname{In} \frac{\mathrm{V}_{\mathrm{f}}}{\mathrm{V}_{1}}\) (c) \(\frac{\Delta \mathrm{G}_{\text {Syslem }}}{\Delta \mathrm{S}_{\text {total }}}=-\mathrm{T}\) (d) \(\mathrm{K}=\mathrm{e}^{\Delta \mathrm{G}^{\circ} / \mathrm{RT}}\)

A piston filled with \(0.04\) mol of an ideal gas expands reversibly from \(50.0 \mathrm{~mL}\) to \(375 \mathrm{~mL}\) at a constant temperature of \(37.0^{\circ} \mathrm{C}\). As it does so, it absorbs \(208 \mathrm{~J}\) of heat. The values of \(\mathrm{q}\) and \(\mathrm{w}\) for the process will be: \((\mathrm{R}=3.314 \mathrm{~J} / \mathrm{mol} \mathrm{K})(\operatorname{Ln} 7.5=2.01)\) (a) \(\mathrm{q}=-208 \mathrm{~J}, \mathrm{w}=+208 \mathrm{~J}\) (b) \(\mathrm{q}=+208 \mathrm{~J}, \mathrm{w}=+208 \mathrm{~J}\) (c) \(\mathrm{q}=+208 \mathrm{~J}, \mathrm{w}=-208 \mathrm{~J}\) (d) \(\mathrm{q}=-208 \mathrm{~J}, \mathrm{w}=-208 \mathrm{~J}\)

For complete combustion of ethanol, \(\mathrm{C}_{2} \mathrm{H}_{5} \mathrm{OH} \ell+\) \(3 \mathrm{O}_{2}(\mathrm{~g}) \rightarrow 2 \mathrm{CO}_{2}(\mathrm{~g})+3 \mathrm{H}_{2} \mathrm{O} \ell\) the amount of heat produced as measured in bomb calorimeter, is \(1364.47 \mathrm{~kJ}\) \(\mathrm{mol}^{-1}\) at \(25^{\circ} \mathrm{C}\). Assuming ideality the Enthalpy of combustion, \(\Delta_{\mathrm{c}} \mathrm{H}\) for the reaction will be: \(\left(\mathrm{R}=8.314 \mathrm{~kJ} \mathrm{~mol}^{-1}\right)\) (a) \(-1460.50 \mathrm{kj} \mathrm{mol}^{-1}\) (b) \(-1350.50 \mathrm{~kJ} \mathrm{~mol}^{-1}\) (c) \(-1366.95 \mathrm{~kJ} \mathrm{~mol}^{-1}\) (d) \(-1361.95 \mathrm{~kJ} \mathrm{~mol}^{-1}\)

The heats of combustion of carbon and carbon monoxide are \(-393.5\) and \(-283.5 \mathrm{~kJ} \mathrm{~mol}^{-1}\), respectively. The heat of formation (in \(\mathrm{kJ}\) ) of carbon monoxide per mole is: (a) \(676.5\) (b) \(-676.5\) (c) \(-110.5\) (d) \(110.5\)

At \(300 \mathrm{~K}\) and \(1 \mathrm{~atm}, 15 \mathrm{~mL}\) a gaseous hydrocarbon requires \(375 \mathrm{~mL}\) air containing \(20 \% \mathrm{O}_{2}\) by volume for complete combustion. After comustion the gases occupy \(330 \mathrm{~mL}\). Assuming that the water formed is in liquid form and the volumes were measured at the same temperature and pressure, the formula of the hydrocarbon is: (a) \(\mathrm{C}_{3} \mathrm{H}_{8}\) (b) \(\mathrm{C}_{4} \mathrm{H}_{8}\) (c) \(\mathrm{C}_{4} \mathrm{H}_{10}\) (d) \(\mathrm{C}_{3} \mathrm{H}_{6}\)