Depression in Freezing Point of the Solvent

IMPORTANT

Depression in Freezing Point of the Solvent: Overview

This Topic covers sub-topics such as Depression in Freezing Point, Anti-Freezing Agents, Molal Freezing Point Depression Constant and, Molal Freezing Point Depression Constant Using Molar Heat of Fusion

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 of an aqueous solution of KCN containing 0.2 mole/kg water was -0.80°C. On adding 0.1 mole of HgCN2 in the solution containing 1 kg of water, the freezing point of the solution was -0.6°C. Assuming that the complex is formed according to the following equation HgCN2+mCN-HgCNm+2m- and HgCN2 is the limiting reactant, the value of m is

EASY
IMPORTANT

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

Reason :Sodium chloride depresses the freezing point of water.

EASY
IMPORTANT

Which of the following statements is false?

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

MEDIUM
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If van't Hoff factor for KCl is 1.8. What is the boiling point of 0.75 m  solution of KCl in water Kb=0.5°Ckg/mol?
 

MEDIUM
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The freezing point (in C) of a solution containing 0.1 g of K3Fe(CN)6 (Mol.wt.329)  in 100 g of water Kf=1.86 K kg mol-1 is :

MEDIUM
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An aqueous solution containing 6% by weight of urea and 9% by weight of glucose. What will be its approximate freezing point? KfH2O=1.86 K kg mol-1

MEDIUM
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Which of the following aqueous solution has highest melting point ?

MEDIUM
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A 0.2 molal aqueous solution of a weak acid HX is 20% ionised. The freezing point of this solution is:

MEDIUM
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The depression in freezing point of 0.01M aqueous CH3COOH solution is 0.02046°1 M urea solution freezes at -1.86°C. Assuming molality equal to molarity, pH of CH3COOH solution is :

EASY
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An aqueous solution of 10% NaCl (ideal) is cooled. It will allow some

MEDIUM
IMPORTANT

Highest freezing point will be observed for which aqueous solution?

MEDIUM
IMPORTANT

The freezing point of benzene decreases by 0.45°C when 0.2g of acetic acid is added to 20g of benzene. If acetic acid associates to form a dimer in benzene, percentage association of acetic acid in benzene will be: Kffor benzene=5.12 K kg mol-1)

MEDIUM
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The change of energy on freezing 1.00 kg of liquid water of 0°C and 1 atm is :

ΔHice fusion =6.01 kJ/mol

MEDIUM
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A 0.001 molal solution of PtNH34Cl4 in water has a freezing point depression of 0.0054°C. If Kf of water is 1.80, then correct formulation of above molecule is :

MEDIUM
IMPORTANT

A compound is known to be a salt of sodium NaX. If 2 g of salt is dissolved in 100 g of water, the solution freezes at -1.27°C. What will be the compound NaX ? (Kf of water is 1.86 K kg/mol.)