Colligative properties

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

The elevation in boiling point for 1 molal solution of non-volatile solute A is 3 K. The depression in freezing point for 2 molal solution of A in the same solvent is 6 K. The ratio of $K_b$ and $K_f$ i.e., $K_b/K_f$ is 1 : X. The value of X is [nearest integer]

Boiling point of a 2% aqueous solution of a non-volatile solute A is equal to the boiling point of 8% aqueous solution of a non-volatile solute B. The relation between molecular weights of A and B is

When a certain amount of solid A is dissolved in 100 g of water at 25°C to make a dilute solution, the vapour pressure of the solution is reduced to one-half of that of pure water. The vapour pressure of pure water is 23.76 mmHg. The number of moles of solute A added is ______. (Nearest Integer)

150 g of acetic acid was contaminated with 10.2 g ascorbic acid $(\mathrm{C_6H_8O_6})$ to lower down its freezing point by $(x\times10^{-1})$°C. The value of $x$ is ______. (Nearest integer)

[Given $K_f$ = 3.9 K kg mol$^{-1}$; molar mass of ascorbic acid = 176 g mol$^{-1}$]

1.80 g of solute A was dissolved in 62.5 cm$^3$ of ethanol and freezing point of the solution was found to be 155.1 K. The molar mass of solute A is _______ g mol$^{-1}$.

[Given: Freezing point of ethanol is 156.0 K. Density of ethanol is 0.80 g cm$^{-3}$. Freezing point depression constant of ethanol is 2.00 K kg mol$^{-1}$]

31 g of ethylene glycol is mixed with 500 g of water. The freezing point of the aqueous solution is _______ K. (in nearest integer)

(K$_f$ of water = 1.86 K kg mol$^{-1}$)

[Molar mass of C, H, O are 12, 1, 16 g mol$^{-1}$]

The value of $\mathbf x$ is ____.

The value of $|\mathbf y|$ is ____.

On dissolving 0.5 g of a non-volatile non-ionic solute to 39 g of benzene, its vapor pressure decreases from 650 mm Hg to 640 mm Hg. The depression of freezing point of benzene (in K) upon addition of the solute is ______

(Given data: Molar mass and the molal freezing point depression constant of benzene are 78 g mol⁻¹ and 5.12 K kg mol⁻¹, respectively)

The plot given below shows $P-T$ curves (where $P$ is the pressure and $T$ is the temperature) for two solvents X and Y and isomolal solutions of NaCl in these solvents. NaCl completely dissociates in both the solvents.

On addition of equal number of moles of a non-volatile solute S in equal amount (in kg) of these solvents, the elevation of boiling point of solvent X is three times that of solvent Y. Solute S is known to undergo dimerization in these solvents. If the degree of dimerization is 0.7 in solvent Y, the degree of dimerization in solvent X is ______.

Pure water freezes at 273 K and 1 bar. The addition of 34.5 g of ethanol to 500 g of water changes the freezing point of the solution. Use the freezing point depression constant of water as $2\ \mathrm{K\,kg\,mol^{-1}}$. The figures shown below represent plots of vapour pressure (V.P.) versus temperature (T). [molecular weight of ethanol is $46\ \mathrm{g\,mol^{-1}}$]

Among the following, the option representing change in the freezing point is

The freezing point of benzene decreases by 0.45°C when 0.2 g of acetic acid is added to 20 g of benzene. If acetic acid associates to form a dimer in benzene, percentage association of acetic acid in benzene will be :

($K_f$ for benzene = 5.12 K kg mol$^{-1}$)

5 g of $\ce{Na2SO4}$ was dissolved in $x$ g of $\ce{H2O}$. The change in freezing point was found to be 3.82°C. If $\ce{Na2SO4}$ is 81.5% ionised, the value of $x$ ($K_f$ for water = 1.86°C kg mol$^{-1}$) is approximately :

(molar mass of S = 32 g mol$^{-1}$ and that of Na = 23 g mol$^{-1}$)

If the freezing point of a 0.01 molal aqueous solution of a cobalt(III) chloride-ammonia complex (which behaves as a strong electrolyte) is −0.0558 °C, the number of chloride(s) in the coordination sphere of the complex is

[$K_f$ of water = 1.86 K kg mol⁻¹]

The vapour pressure of acetone at 20°C is 185 torr. When 1.2 g of a non-volatile substance was dissolved in 100 g of acetone at 20°C, its vapour pressure was 183 torr. The molar mass (g mol$^{-1}$) of the substance is :

Determination of the molar mass of acetic acid in benzene using freezing point depression is affected by :

$\ce{MX2}$ dissociates into $\ce{M^{2+}}$ and $\ce{X-}$ ions in an aqueous solution, with a degree of dissociation ($\alpha$) of 0.5. The ratio of the observed depression of freezing point of the aqueous solution to the value of the depression of freezing point in the absence of ionic dissociation is

Consider separate solutions of 0.500 M $\ce{C2H5OH(aq)}$, 0.100 M $\ce{Mg3(PO4)2(aq)}$, 0.250 M $\ce{KBr(aq)}$ and 0.125 M $\ce{Na3PO4(aq)}$ at 25°C. Which statement is true about these solutions, assuming all salts to be strong electrolytes ?