Relative Lowering of Vapor Pressure

IMPORTANT

Relative Lowering of Vapor Pressure: Overview

This topic covers concepts, such as, Colligative Properties, Relative Lowering of Vapour Pressure, Factors Affecting Colligative Properties & Ostwald and Wacker's Experiment etc.

Important Questions on Relative Lowering of Vapor Pressure

MEDIUM
IMPORTANT

Which among the following is a colligative property? 

EASY
IMPORTANT

The mass of a non-volatile, non-electrolyte solute (molar mass = 50 g mol-1 ) needed to be dissolved in 114 g octane to reduce its vapour pressure by 75 %, is:

MEDIUM
IMPORTANT

A solution X contains 12 g of urea per litre of water. Another solution Y contains 68.4 g of cane sugar per litre of water at the same temperature. What is the ratio of lowering of vapour pressure in solutions of X and Y?

N=14 u, C=12 u, O=16 u, H=1 u

MEDIUM
IMPORTANT

What is the vapour pressure of a solution containing 15.6 g of water and 1.68 g of sucrose C12H22O11 at 100° C?

Give your answer by rounding off to the nearest integer value.Molecular weight of sucrose is 342.

MEDIUM
IMPORTANT

The pressure of the water vapour of a solution containing a non-volatile solute is 2% below that of the vapour of pure water. Determine the molality of the solution.

Round off your answer to nearest integer value.

HARD
IMPORTANT

Question Image

X= Mole fraction of liquid A in liquid solution.

Y= Mole fraction of vapour A in vapour mixture.

Z is the graphical mid point between "1" & "X".

Find value of P.Y.100X. [Given :PT=450 mmHg]

If PA'=300 mm of Hg

PB=700 mm of Hg

Give your answer after multiplying with 10 and round off to the nearest integer.

HARD
IMPORTANT

Two beaker are placed in a sealed flask. Beaker A initially contained 0.15 mol of naphthalene (non-volatile) in 117 g of benzene and beaker B initially contained 31 g of an unknown compound (non-volatile, non-electrolytic) in 117 g of benzene. At equilibrium, beaker A is found to have lost 7.8 g of weight. Assume ideal behaviour of both solutions to answer the following question.

The molar mass of solute in solution B is closest to:

EASY
IMPORTANT

Relative lowering of vapour pressure is a colligative property because _____.

EASY
IMPORTANT

Colligative properties depend on _____.

EASY
IMPORTANT

Relative vapour pressure lowering depends only on.

EASY
IMPORTANT

Vapour pressure of solution of a non volatile solute is always

EASY
IMPORTANT

Lowering of the vapour pressure of the solution:

EASY
IMPORTANT

A solution of methanol and ethanol has a vapour pressure of P=119x+135 at 400C, where x is the mole fraction of methanol. Hence,

MEDIUM
IMPORTANT

Identify the inappropriate statement.

EASY
IMPORTANT

Find the value of mole fraction of the solute when vapour pressure of glucose is 750 mm Hg at 373 K in dilute solution.

MEDIUM
IMPORTANT

Consider the following statements.
(i) On adding Methyl alcohol to water, boiling point of water increases.
(ii) When NaCl is added to water, depression in freezing point is observed.
(iii) Diffusion of solvent occurs from a region of its higher concentration to a region of its lower concentration.
Identify the correct options.

MEDIUM
IMPORTANT

Find the correct relation between pKa1 and pKa2 of acids HA1 and HA2 (assuming they are taken in same concentration), if lowering of vapour pressure $\Delta \mathrm{P}_{1}$ of an aqueous solution of acid HA1 and $\Delta \mathrm{P}_{2}$ of an aqueous solution of acid HA2, are related as P1>P2.
 

EASY
IMPORTANT

Among the following aqueous solutions, which has a lowest boiling point?

HARD
IMPORTANT

An ideal solution of two pure liquids A and B are having the vapour pressure of 100 and 400 torr respectively at the temperature T. The liquid solution of A and B is made up of 1 mole of each A and B. Then, find the pressure when 1 mole of mixture has been vaporised.