Chapter 4

Heat of neutralization of an acid with a base is \(13.7 \mathrm{kcal}\) when (a) both acid and base are weak (b) acid is weak and base is strong (c) acid is strong and base is weak (d) both acid and base are strong

The calorific value of fat is (a) less than that of carbohydrates and protein (b) less than that of protein but more than carbohydrates (c) less than that of carbohydrates but more than that of protein (d) more than that of carbohydrate and protein

In which case, a spontaneous reaction is possible at any temperature ? (a) \(\Delta H-v e, \Delta \bar{S}+v e\) (b) \(\Delta H-v e, \Delta S-v e\) (c) \(\Delta H+\) ve, \(\Delta S+v e\) (d) none of the cases

The work done by a system is \(8 \mathrm{~J}\), when \(40 \mathrm{~J}\) heat is supplied to it. The change in internal energy of the system during the process: (a) \(32 \mathrm{~J}\) (b) \(40 \mathrm{~J}\) (c) \(36 \mathrm{~J}\) (d) \(44 \mathrm{~J}\)

The factor that does not influence the heat of reaction is (a) The physical state of reactants and products (b) The temperature (c) The pressure or volume (d) The method by which the final products are obtained

When \(10 \mathrm{ml}\) of \(0.1 \mathrm{M}\) soln. of \(\mathrm{HCl}\) is mixed with \(10 \mathrm{ml}\) of \(0.1 \mathrm{M}\) of \(\mathrm{KOH}\) solution, the rise in temperature was observed to be \(4^{\circ} \mathrm{C}\). If \(100 \mathrm{ml}\) of \(0.1 \mathrm{M} \mathrm{HCl}\) and \(100 \mathrm{ml}\) of \(0.1 \mathrm{M} \mathrm{KOH}\) are mixed in the same vessel, the rise in temperature would be (a) \(40^{\circ} \mathrm{C}\) (b) \(4^{\circ} \mathrm{C}\) (c) \(20^{\circ}\) (d) unpredictable

An example of extensive property is (a) temperature (b) internal energy (c) viscosity (d) surface tension

The enthalpy of neutralisation of \(\mathrm{NaOH}\) with \(\mathrm{HCl}\) is \(57.1 \mathrm{~kJ}\), while with \(\mathrm{CH}_{3} \mathrm{COOH}\), it is \(-55 \mathrm{~kJ}\). This happens because (a) Acetic acid is an organic acid (b) Acetic acid is little soluble in water (c) Acetic acid is a weak acid and requires lesser sodium hydroxide for neutralisation (d) Some heat is required to ionize acetic acid completely

On the basis of information available from the reaction \(\frac{4}{3} \mathrm{Al}+\mathrm{O}_{2} \rightarrow \frac{2}{3} \mathrm{Al}_{2} \mathrm{O}_{3}: \Delta G=-827 \mathrm{~kJ} \mathrm{~mol}^{-1}\) of \(\mathrm{O}_{2}\), the minimum emf required to carry out electrolysis of \(\mathrm{Al}_{2} \mathrm{O}_{3}\) is \(\left(F=96500 \mathrm{C} \mathrm{mol}^{-1}\right)\) (a) \(8.56 \mathrm{~V}\) (b) \(2.14 \mathrm{~V}\) (c) \(4.28 \mathrm{~V}\) (d) \(6.42 \mathrm{~V}\)

In a chemical reaction \(\Delta H=150 \mathrm{~kJ}\) and \(\Delta S=100 \mathrm{JK}^{-1}\) at \(300 \mathrm{~K}\). the \(\Delta G\) for the reaction is: (a) Zero (b) \(300 \mathrm{~kJ}\) (c) \(330 \mathrm{~kJ}\) (d) \(120 \mathrm{~kJ}\)

In which case, a spontaneous reaction is impossible at any temperature? (a) \(\Delta H+v e, \Delta S+v e\) (b) \(\Delta H+\mathrm{ve}, \Delta S\)-ve (c) \(\Delta H-v e, \Delta S-\) ve (d) In all cases

On combustion carbon forms two oxides \(\mathrm{CO}\) and \(\mathrm{CO}_{2}\). heat of formation of \(\mathrm{CO}_{2}\) is \(-94.3\) kcal and that of \(\mathrm{CO}\) is \(-26.0 \mathrm{kcal}\). Heat of combustion of carbon is (a) \(-26.0 \mathrm{kcal}\) (b) \(-68.3 \mathrm{kcal}\) (c) \(-94.3 \mathrm{kcal}\) (d) \(-120.3 \mathrm{kcal}\)

The heat of formation of \(\mathrm{MgO}, \mathrm{Al}_{2} \mathrm{O}_{3}\) and \(\mathrm{SiO}_{2}\) are \(-602,-1676\) and, \(-911 \mathrm{~kJ} \mathrm{~mol}^{-1}\), respectively, Most stable oxide is (a) \(\mathrm{MgO}\) (b) \(\mathrm{Al}_{2} \mathrm{O}_{3}\) \(\begin{array}{ll}\text { (c) } \mathrm{SiO}_{2} & \text { (d) Cannot be predicted } \\ \text { enfoge }\end{array}\)

The molar enthalpy of fusion of water is \(6.01 \mathrm{~kJ} \mathrm{~mol}^{-1}\). The entharps change of \(1 \mathrm{~mol}\) of water at its melting point will be (a) \(22 \mathrm{~kJ} \mathrm{~mol}^{-1}\) (b) \(109 \mathrm{~kJ} \mathrm{~mol}^{-1}\) (c) \(44 \mathrm{~kJ} \mathrm{~mol}^{-1}\) (d) \(11 \mathrm{~kJ} \mathrm{~mol}^{-1}\)

The heat of neutralisation of strong base and strong acid is \(57.0 \mathrm{~kJ}\); the heat released when \(0.5 \mathrm{~mol}\) of \(\mathrm{HNO}_{3}\) solution is added to \(0.20 \mathrm{~mol}\) of \(\mathrm{NaOH}\) solution is (a) \(57.0 \mathrm{~kJ}\) (b) \(28.5 \mathrm{~kJ}\) (c) \(11.40 \mathrm{~kJ}\) (d) \(34.9 \mathrm{~kJ}\)

An endothermic reaction is spontaneous if (a) \(\Delta H>T \Delta S\) (b) \(\Delta H

If an endothermic reaction is non-spontaneous at freezing point of water and becomes feasible at its boiling point, then (a) \(\Delta H\) is \(-v e, \Delta S\) is \(+\) ve (b) \(\Delta H\) and \(\Delta S\) both are +ve (c) \(\Delta H\) and \(\triangle S\) both are -ve (d) \(\Delta H\) is \(+\mathrm{ve}, \Delta S\) is \(-\mathrm{ve}\)

Assuming 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 \(100^{\circ} \mathrm{C}\), will be: (Given molar enthalpy of vapourization of water at 1 bar and \(373 \mathrm{~K}=41 \mathrm{~kJ} \mathrm{~mol}^{-1}\) and \(R=8.3 \mathrm{JK}^{-1} \mathrm{~mol}^{-1}\) ) (a) \(41.00 \mathrm{~kJ} \mathrm{~mol}^{-1}\) (b) \(4.100 \mathrm{~kJ} \mathrm{~mol}^{-1}\) (c) \(3.7904 \mathrm{~kJ} \mathrm{~mol}^{-1}\) (d) \(37.904 \mathrm{~kJ} \mathrm{~mol}^{-1}\)

The enthalpy and entropy changes for the reaction \(\mathrm{Br}_{2}(1)+\mathrm{Cl}_{2}(\mathrm{~g}) \rightleftharpoons 2 \mathrm{BrCl}(\mathrm{g})\) are \(30 \mathrm{~kJ} \mathrm{~mol}^{-1}\) and \(105 \mathrm{~J} \mathrm{~K}^{-1} \mathrm{~mol}^{-1}\), respectively. The temperature at which the reaction will be in equilibrium is (a) \(285.7 \mathrm{~K}\) (b) \(273 \mathrm{~K}\) (c) \(450 \mathrm{~K}\) (d) \(300 \mathrm{~K}\)

Given that bond energies of \(\mathrm{H}-\mathrm{H}\) and \(\mathrm{Cl}-\mathrm{Cl}\) are \(430 \mathrm{~kJ} / \mathrm{mol}\) and \(240 \mathrm{~kJ} / \mathrm{mol}\), respectively. \(\Delta H_{f}\) for \(\mathrm{HCl}\) is \(-90 \mathrm{~kJ} / \mathrm{mol}\). Bond enthalpy of \(\mathrm{HCl}\) is (a) \(380 \mathrm{~kJ} \mathrm{~mol}^{-1}\) (b) \(425 \mathrm{~kJ} \mathrm{~mol}^{-1}\) (c) \(245 \mathrm{~kJ} \mathrm{~mol}^{-1}\) (d) \(290 \mathrm{~kJ} \mathrm{~mol}^{-1}\)

The enthalpy of combustion of cyclohexane, cyclohexene and \(\mathrm{H}_{2}\) are respectively \(-3920,-3800\) and \(-241 \mathrm{~kJ} \mathrm{~mol}^{-1}\). The heat of hydrogenation of cyclohexene is (a) \(-121 \mathrm{~kJ} \mathrm{~mol}^{-1}\) (b) \(+121 \mathrm{~kJ} \mathrm{~mol}^{-1}\) (c) \(-242 \mathrm{~kJ} \mathrm{~mol}^{-1}\) (d) \(+242 \mathrm{~kJ} \mathrm{~mol}^{-1}\)

In the conversion of lime stone to lime, \(\mathrm{CaCO}_{3}(\mathrm{~s}) \rightarrow \mathrm{CaO}(\mathrm{s})+\mathrm{CO}_{2}(\mathrm{~g})\) The values of \(\Delta H^{\circ}\) and \(\Delta S^{\circ}\) are \(+179.1 \mathrm{~kJ} \mathrm{~mol}^{-1}\) and \(160.2 \mathrm{JK}^{-1} \mathrm{~mol}^{-1}\), respectively at 298 \(\mathrm{K}\) and 1 bar. Assuming that \(\Delta H^{\circ}\) and \(\Delta S^{\circ}\) do not change with temperature; temperature above which conversion of lime stone to lime will be spontaneous is (a) \(1118 \mathrm{~K}\) (b) \(1008 \mathrm{~K}\) (c) \(1200 \mathrm{~K}\) (d) \(845 \mathrm{~K}\)

The amount of heat measured for a reaction in a bomb calorimeter is (a) \(\Delta G\) (b) \(\Delta H\) (c) \(\Delta E\) (d) \(P \Delta V\)

Calculate the enthalpy change for the following: \(400 \mathrm{ml}\) of \(0.2 \mathrm{M} \mathrm{H}_{2} \mathrm{SO}_{4}\) added to \(300 \mathrm{ml}\) of \(0.1 \mathrm{M} \mathrm{KOH}\). (a) \(-3.43 \mathrm{~kJ}\) (b) \(-1.71 \mathrm{~kJ}\) (c) \(-6.86 \mathrm{~kJ}\) (d) \(-10.29 \mathrm{~kJ}\)