Solutions and Colligative Properties

Molecules of benzoic acid (C₆H₅COOH) dimerise in benzene. 'w' g of the acid dissolved in 30 g of benzene shows a depression in freezing point equal to 2K. If the percentage association of the acid to form dimmer in the solution is 80, then w is – (Its given that K_f = 5 K kg mol^–1, Molar mass of benzoic acid = 122 g mol^–1)

Molal depression constant for a solvent is 4.0 kg mol^–1. The depression in the freezing point of the solvent for 0.03 mol kg^–1 solution of K₂SO₄ is : (Assume complete dissociation of the electrolyte)

K₂Hgl₄ is 40% ionised in aqueous solution. The value of its van't Hoff factor (i) is:

The freezing point of a diluted milk sample is found to be –0.2^oC, while it should have been –0.5^oC for pure milk. How much water has been added to pure milk to make the diluted sample?

Which one of the following 0.06 M aqueous solutions has lowest freezing point?

Solute A associates in water. When 0.7 g of solute A is dissolved in 42.0 g of water, it depresses the freezing point by 0.2$^\circ$C. The percentage association of solute A in water, is : [Given : Molar mass of A = 93 g mol^$-$1. Molal depression constant of water is 1.86 K kg mol^$-$1.]

The depression in freezing point observed for a formic acid solution of concentration $0.5 \mathrm{~mL} \mathrm{~L}^{-1}$ is $0.0405^{\circ} \mathrm{C}$. Density of formic acid is $1.05 \mathrm{~g} \mathrm{~mL}^{-1}$. The Van't Hoff factor of the formic acid solution is nearly : (Given for water $\mathrm{k}_{\mathrm{f}}=1.86\, \mathrm{k} \,\mathrm{kg}\,\mathrm{mol}^{-1}$ )

Two solutions A and B are prepared by dissolving 1 g of non-volatile solutes X and Y, respectively in 1 kg of water. The ratio of depression in freezing points for A and B is found to be 1 : 4. The ratio of molar masses of X and Y is

Evaluate the following statements for their correctness. A. The elevation in boiling point temperature of water will be same for $0.1 \mathrm{M} \, \mathrm{NaCl}$ and $0.1 \mathrm{M}$ urea. B. Azeotropic mixtures boil without change in their composition. C. Osmosis always takes place from hypertonic to hypotonic solution. D. The density of $32 \% \, \mathrm{H}_{2} \mathrm{SO}_{4}$ solution having molarity $4.09 ~\mathrm{M}$ is approximately $1.26 \mathrm{~g} \mathrm{~mL}^{-1}$ E. A negatively charged sol is obtained when KI solution is added to silver nitrate solution. Choose the correct answer from the options given below :

Match List I with List II .tg {border-collapse:collapse;border-spacing:0;} .tg td{border-color:black;border-style:solid;border-width:1px;font-family:Arial, sans-serif;font-size:14px; overflow:hidden;padding:10px 5px;word-break:normal;} .tg th{border-color:black;border-style:solid;border-width:1px;font-family:Arial, sans-serif;font-size:14px; font-weight:normal;overflow:hidden;padding:10px 5px;word-break:normal;} .tg .tg-7btt{border-color:inherit;font-weight:bold;text-align:center;vertical-align:top} .tg .tg-0pky{border-color:inherit;text-align:left;vertical-align:top} List I List II A. van't Hoff factor, i I. Cryoscopic constant B. $\mathrm{k_f}$ II. Isotonic solutions C. Solutions with same osmotic pressure III. $\mathrm{\frac{Normal\,molar\,mass}{Abnormal\,molar\,mass}}$ D. Azeotropes IV. Solutions with same composition of vapour above it Choose the correct answer from the options given below :