Raoult's Law

Q. The vapour pressure of an aqueous solution is found to be $750\text{torr}$ at certain temperature ${}^{\prime }{T}^{\prime }$. If ${}^{\prime }{T}^{\prime }$ is the temperature at which pure water boils under atmospheric pressure and same solution show elevation in boiling point $\Delta T_b=1.04\text{K}$, then let the atmospheric pressure be $x$. Find $\frac{x}{111}$ $(K_b=0.52{\text{k kg mol}}^{-1})$

Q.

A solution that obeys Raoult's law is:

1. Normal

2. Ideal

3. Saturated

4. Molar

Q.

The vapour pressure will be lowest for

1. 0.1 M sugar solution

2. 0.1 M KCl solution

3. 0.1 M Cu(NO₃)₂ solution

4. 0.1 M AgNO₃ solution

Q.

Vapour pressure of a solution is:

1. Directly proportional to the mole fraction of the solvent
2. Inversely proportional to the mole fraction of the solute
3. Inversely proportional to the mole fraction of the solvent
4. Directly proportional to the mole fraction of the solute

Q. Binary liquid mixtures which exhibit positive deviations from Raoult's law boil at temperature ______ than the expected boiling point:

1. Lower

2. Higher

3. Same

4. Con't be said

Q.

Which solution will show the maximum vapour pressure at 300 K?

1. 1MC₁₂H₂₂O₁₁

2. 1MNaCl₂

3. 1MCH₃COOH

4. 1MNaCl

Q.

Which of the following solutions in water will have the lowest vapour pressure

1. 0.1 M, NaCl

2. 0.1 M, Sucrose

3. 0.1 M, BaCl₂

4. 0.1 M Na₃PO₄

Q.

When a substance is dissolved in a solvent the vapour pressure of the solvent is decreased. This results in:

1. An increase in the b.p. of the solution
2. A decrease in the b.p. of the solvent
3. The solution having a higher freezing point than the solvent
4. The solution having a lower osmotic pressure than the solvent

Q.

The vapour pressure of pure benzene and toluene are 160 and 60 torr respectively. The mole fraction of toluene in vapour phase in contact with the equimolar solution of benzene and toluene is

1. 0.50

2. 0.6

3. 0.27

4. 0.73

Q.

At a given temperature, the total vapour pressure (in Torr) of a mixture of volatile components A and B is given by P = 120 - 75 XBhence vapour pressure of pure A and B respectively (in Torr) are -

1. 120, 75

2. 120, 195

3. 75, 45

4. 120, 45