## Filters

Q&A - Ask Doubts and Get Answers
Q

# Tell me? An aqueous solution of 2%non-volatile solute exerts pressure of 1.004 bar at the normal boiling point of solvent. The molar mass of the solute is g/mol is

An aqueous solution of 2% non-volatile solute exerts pressure of 1.004 bar at the normal boiling point of solvent. The molar mass of the solute is g/mol is

• Option 1)

85.42

• Option 2)

41.35

• Option 3)

90

• Option 4)

94.42

167 Views

As learnt in

Rault's Law -

The total vapour pressure of binary mixture of miscible liquids be having ideally is given by

$P_{T}= P_{A}^{0}x_{A}+P_{B}^{0}x_{B}$

Where $x_{A}$  and  $x_{B}$ are mole fraction of A and B in liquid phase.

- wherein

$P_{A}^{0}$  and $P_{B}^{0}$ are vapour pressures of pure liquids.

$\frac{p{_{1}}^{0}-p_{1}}{p{_{1}}^{0}}= \frac{w_{2}\times M_{1}}{M_{2}\times w_{1}}$

$\frac{1.013\cdot 1.004}{1.013}= \frac{2\times 18}{M_{2}\times 98}$

$\Rightarrow M_{2} = \frac{2\times 18\times 0.013}{0.009\times 98} = 41.35 g\ mol^{-1}$

Option 1)

85.42

This option is incorrect

Option 2)

41.35

This option is correct

Option 3)

90

This option is incorrect

Option 4)

94.42

This option is incorrect

Exams
Articles
Questions