Dimer of acetic acid in liquid benzene is in equilibrium with acetic acid monomer at certain temperature and pressure. If 25% of the dimer molecules are separated out then

1. Freezing point of the solution reduces

2. Average molar mass of solute increases

3. Boiling point of solution increases

4. Molar mass of solute decreases

The vapour pressure of an aqueous solution of sucrose at 373 K is found to be 750 mm Hg.
The molality of the solution at the same temperature will be:

At 28oC, the vapour pressure of pure liquid A (mol.wt = 40) is 100 torr, while that of pure liquid B is 40 torr, (mol. wt = 80). The vapour pressure at 25^oC of a solution containing 20 g of each A and B is:

1. 80 torr

2. 59.8 torr

3. 68 torr

4. 48 torr

Depression in freezing point of 0.01 molal aqueous HCOOH solution is 0.02046. 1 molal aqueous urea solution freezes at -1.86^oC, assuming molality equal to molarity, pH of HCOOH solution is :

1. 2

2. 3

3. 4

4. 5

The freezing point of a 4% aqueous solutions of 'A' is equal to the freezing point of 10% aqueous solution of 'B'. If the molecular weight of 'A' is 60, then the molecular weight of 'B' will be:

1. 160

2. 90

3. 45

4. 180

How much ethyl alcohol must be added to 1.0 L of water so that solution will not freeze at -4$°$F ? (K_f = 1.86$°$C/m)

1. < 20 g

2. < 10.75 g

3. < 494.5 g

4. > 494.5 g

${\mathrm{C}}_6{\mathrm{H}}_6$ freezes at 5.5$°$C. At what temperature will a solution of 10.44 g of ${\mathrm{C}}_4{\mathrm{H}}_{10}$ in 200 g of ${\mathrm{C}}_6{\mathrm{H}}_6$ freeze ? K_f (${\mathrm{C}}_6{\mathrm{H}}_6$) = 5.12$°$C/m

1. 4.60$°$C

2. 0.89$°$C

3. 5.50$°$C

4. None of the above

The degree of dissociation of an electrolyte is $\mathrm{\alpha }$ and its van't Hoff factor is i. The number of ions obtained by complete dissociation of 1 molecule of the electrolyte is :

1. $\frac{\mathrm{i}+\mathrm{\alpha }-1}{\mathrm{\alpha }}$

2. $\mathrm{i}-\mathrm{\alpha }-1$

3. $\frac{\mathrm{i}-1}{\mathrm{\alpha }}$

4. $\frac{\mathrm{i}+1+\mathrm{\alpha }}{1-\mathrm{\alpha }}$

If two liquids A $\left({\mathrm{P}}_{\mathrm{A}}^0=100 \mathrm{torr}\right)$ and B $\left({\mathrm{P}}_B^0=200 \mathrm{torr}\right)$ are completely immiscible with each other ( each one will behave independtly of the other ) are present in a closed vessel. The total vapour pressure of the system will be :

1. less than 100 torr

2. greater than 200 torr

3. between 100 to 200 torr

4. 300 torr

When a liquid that is immiscible with water was steam distilled at 95.2^oC at a total pressure of 748 torr, the distillate contained 1.25 g of the liquid per gram of water . The vapour pressure of water is 648 torr at 95.2^oC, what is the molar mass of liquid ?

1. 7.975 g/mol

2. 166 g/mol

3. 145.8 g/mol

4. None of these