Problem 149
For an aqueous solution, freezing point is \(-0.186^{\circ} \mathrm{C}\). Elevation of the boiling point of the same solution is $$ \left(\mathrm{K}_{\ell}=1.86^{\circ} \mathrm{mol}^{-1} \mathrm{~kg} \text { and } \mathrm{K}_{\mathrm{b}}=0.512^{\circ} \mathrm{mol}^{-1} \mathrm{~kg}\right) $$ (a) \(0.186^{\circ}\) (b) \(0.0512^{\circ}\) (c) \(1.86^{\circ}\) (d) \(5.12^{\circ}\)
Problem 150
In a \(0.2\) molal aqueous solution of a weak acid HX, the degree of ionization is \(0.3 .\) Taking \(K_{f}\) for water as \(1.85 \mathrm{k} \mathrm{kg}\) melt, the freezing point of the solution will be nearest to (a) \(-0.480^{\circ} \mathrm{C}\) (b) \(-0.360^{\circ} \mathrm{C}\) (c) \(-0.260^{\circ} \mathrm{C}\) (d) \(+0.480^{\circ} \mathrm{C}\)
Problem 151
If liquids A and B form an ideal solution, the (a) enthalpy of mixing is zero (b) entropy of mixing is zero (c) free energy of mixing is zero (d) free energy as well as the entropy of mixing are each zero
Problem 152
If liquids A and B form an ideal solution, the [2003] (a) enthalpy of mixing is zero(b) entropy of mixing is zero (c) free energy of mixing is zero (d) free energy as well as the entropy of mixing are each zero
Problem 153
Which one of the following aqueous solutions will exhibit highest boiling point? (a) \(0.05 \mathrm{M}\) glucose (b) \(0.01 \mathrm{M} \mathrm{KNO}_{3}\) (c) \(0.015 \mathrm{M}\) urea (d) \(0.01 \mathrm{M} \mathrm{Na}_{2} \mathrm{SO}_{4}\)
Problem 154
Which of the following liquid pairs shows a positivedeviation from Raoult' law? (a) water-nitric acid (b) water-hydrochloric acid (c) benzene-methanol (d) acetone-chloroform
Problem 156
If a is the degree of dissociation of \(\mathrm{Na}_{2} \mathrm{SO}_{4}\) the van't Hoff factor (i) used for calculating the molecular mass is (a) \(1+\alpha\) (b) \(1-\alpha\) (c) \(1+2 \alpha\) (d) \(1-2 \alpha\)
Problem 157
Benzene and toluene form nearly ideal solutions. At \(20^{\circ} \mathrm{C}\), the vapour pressure of benzene is 75 torr and that of toluene is 22 torr. The partial vapour pressure of benzene at \(20^{\circ} \mathrm{C}\) for a solution containing \(78 \mathrm{~g}\) of benzene and \(46 \mathrm{~g}\) of toluene in torr is (a) 25 (b) 50 (c) \(37.5\) (d) \(53.5\)
Problem 158
Two solutions of a substance (non-electrolyte) are mixed in the following manner. \(480 \mathrm{~mL}\) of \(1.5 \mathrm{M}\) first solution \(+520 \mathrm{~mL}\) of \(1.2 \mathrm{M}\) second solution. What is the molarity of the final mixture? (a) \(1.344 \mathrm{M}\) (b) \(2.70 \mathrm{M}\) (c) \(1.50 \mathrm{M}\) (d) \(1.20 \mathrm{M}\)
Problem 159
Density of a \(2.05 \mathrm{M}\) solution of acetic acid in water is \(1.02 \mathrm{~g} / \mathrm{mL}\). The molality of the solution is (a) \(1.14 \mathrm{~mol} \mathrm{~kg}^{-1}\) (b) \(3.28 \mathrm{~mol} \mathrm{~kg}^{-1}\) (c) \(2.28 \mathrm{~mol} \mathrm{~kg}^{-1}\) (d) \(0.44 \mathrm{~mol} \mathrm{~kg}^{-1}\)
