Depression in Freezing Point of the Solvent

IMPORTANT

Depression in Freezing Point of the Solvent: Overview

This topic covers concepts, such as Depression in Freezing Point, Molal Freezing Point Depression Constant, Molal Freezing Point Depression Constant Using Molar Heat of Fusion, and Molecular Mass of a Solute through Depression of Freezing Point.

Important Questions on Depression in Freezing Point of the Solvent

HARD
IMPORTANT

What mass of ethylene glycol (molar mass =62.0g​ mol1)  must be added to 5.50 kg of water to lower the freezing point of water from  0°C to10.0°C?  (Kf  forwater=1.86Kkgmol1)

HARD
IMPORTANT

Calculate the depression in the freezing point of water when 10 g of  CH3CH2CHClCOOH is added to 250 g of water.  Ka=1.4×103, Kf=1.86 K kg mol1.

HARD
IMPORTANT

Calculate the freezing point of a solution containing 18 g glucose, C6H12O6and68.4gsucrose,C12H22O11in200g of water. The freezing point of pure water is 273 K and Kf for water is 1.86 K kg mol1.

HARD
IMPORTANT

The freezing point of a solution containing 0.2 g of acetic acid in 20.0 g of benzene is lowered by 0.45°C. The molar mass (g/mol) of acetic acid from this data and the value of van’t Hoff factor would be (for benzene, Kf=5.12 K kg mol-1)

HARD
IMPORTANT

The freezing point depression constant Kf of benzene is 5.12Kkg mol-1. Assuming 100% dimerization of acetic acid in benzene, the freezing point depression of 0.2m solution of acetic acid is

EASY
IMPORTANT

If sodium sulphate is considered to be completely dissociated into cations and anions in an aqueous solution, the change in the freezing point of water, when 0.01 mol of sodium sulphate is dissolved in 1 Kg of water, is Kf=1.86 K Kg mol-1

EASY
IMPORTANT

Ethylene glycol is used as an antifreeze in cold climates. Mass of ethylene glycol which should be added to 4 Kg of water to prevent it from freezing at -6° C will be: [Kf for water =1.86 K Kg mol-1, and molar mass of ethylene glycol =62 g mol-1]

EASY
IMPORTANT

Camphor is often used in molecular mass determination because 

EASY
IMPORTANT

The molal freezing constant of water is 1.86° C/M. Therefore, the freezing point of 0.1 mNaCl solution in water expected to be

MEDIUM
IMPORTANT

Calculate the amount of ice separated out from this solution if the solution of 18 g of glucose in 1000 g of water is cooled to -0.2°C.

MEDIUM
IMPORTANT

The freezing point of equimolal aqueous solutions will be highest for

EASY
IMPORTANT

Assertion: Camphor is usually used in molecular mass determination.

Reason: Camphor has low cryoscopic constant and therefore, causes greater depression in freezing point.

EASY
IMPORTANT

Assertion: Sodium chloride is used to clear snow on the roads.

Reason :Sodium chloride depresses the freezing point of water.

HARD
IMPORTANT

PtCl4·6H2O can exist as a hydrated complex. 1 molal aqueous solution has a depression in freezing point of 3.72°C. Assume, 100% ionization and Kf H2O=1.86 K mol-1 kg. Then the complex is

EASY
IMPORTANT

Which of the following statements is false?

HARD
IMPORTANT

The freezing point of an equimolal aqueous solution will be the highest for

MEDIUM
IMPORTANT

The depression in freezing point of 0.01 m aqueous solution of urea, sodium chloride and sodium sulphate is in the ratio :

HARD
IMPORTANT

Which is the correct relationship between molal depression constant and enthalpy of fusion ?

HARD
IMPORTANT

1.00 g of a non-electrolyte solute dissolved in 50 g of benzene lowered the freezing point of benzene by 0.40 K. The freezing point depression constant of benzene is 5.12 K kg mol-1. Find the molar mass of the solute.

MEDIUM
IMPORTANT

Which of the following will have maximum depression in freezing point?