Solutions

The vapour pressures of A and B at 25°C are 90mm Hg and 15mm Hg respectively. If A and B are mixed such that the mole fraction of A in the mixture is 0.6, then mole fraction of B in the vapour phase is x * 10^-1. The value x is_________. (Nearest Integer)

An aqueous KCl solution of density 1.2 mL^-1 has a molality of 3.30 mol kg^-1. The molarity of the solution in mol L^-1 is__________(Nearest integer)

[Molar mass of KCl = 74.5]

Of the following four aqueous solutions, total number of those solutions whose freezing point is lower than that of 0.10 M C₂H₅OH is___________

(Integer answer)

Solute A associate in water. When 0.7g of solute A is dissolved in 42.0g of water it depresses the freezing point by $0.2°C$ . 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.]

2g of a non-volatile non-electrolyte solute is dissolved in 200g of two different solvents A and B whose ebullioscopic constant are in the ratio of 1:8. The elevation in boiling points of A and B are in the ratio $\frac{x}{y}\left(x:y\right).$  The value of y is __________. (Nearest integer)

Given below are two statements: one is labeled as Assertion (A) and the other is labeled as Reason (R)

Assertion (A): At 10°C, the density of a 5M solution of KCl [atomic masses of K % Cl are 39 & 35.5 g mol^-1 respectively is 'x' g ml^-1. The solution is cooled to -21°C. The molality of the solution will remain unchanged.

Reason (R) : The molality of a solution does not change with temperature as mass remains unaffected with temperature

In the light of the above statements, choose the correct answer from the options given below.

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 $K_f=1.86kkgmo{l}^{-1}$ ${}_{}{}^{}$ )

250g solution of D-glucose in water contains 10.8% of carbon by weight. The molality of the solution is nearest to

(Given : Atomic weights are, H, 1u ; C, 12u ; O, 16u)

When a certain amount of solid A is dissolved in 100g 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)

 1.80g of solute A was dissolved in 62.5cm³ 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]