Chemistry Solutions

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)

83 g of ethylene glycol dissolved in 625 g of water. The freezing point of the solution is________K. (Nearest integer).

[Use: Molal Freezing point depression constant of water = 1.86 K kg mol^-1

Freezing point of water = 273K

Atomic masses: C : 12.0u, O : 16.0u, H : 1.0u]

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.]

Two solutions A and B are prepared by dissolving 1g of no-volatile solutes X and Y respectively in 1 kg of water. The ratio of depression in freezing point for A and B is found to be 1 : 4. The ratio of molar masses of X and Y is

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

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

 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]

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)

150g of acetic acid was contaminated with 10.2g ascorbic acid $\left(C_6{H}_8{O}_6\right)$  to lower down its freezing point by (x * 10^-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]