The freezing point depression constant format is -1.86°C m^-1. If 5.00g Na₂SO₄ dissolved

in 45.0 g H₂O, the freezing point is changed by -3.82°C. Calculate the van't Hoff factor

for NaSO4

1. 2.63

2. 3.11

3. 0.381

4. 2.05

The van't Hoff factor, i for a compound which undergoes dissociation in one solvent and

association in other solvent is respectively.

1. less than one and less than one

2. greater than one and less than one

3. greater than one and greater than one

4. less than one and greater than one

An aqueous solution is 1.00 molal in KI. Which change will cause the vapour pressure of

the solution to increase ?

1. Addition of NaCl

2. Addition of Na₂SO₄

3. Addition of 1.00 molal KI

4. Addition of water

A solution of sucrose (molar mass = 342 g mol^-1) has been prepared by dissolving 68.5 g of sucrose in 1000 g of water.

The freezing point of the solution obtained will be:

 (K_f for water = 1.86 K kg mol^-1)

1. -0.372 $°$C

2. 0.372 $°$C

3. 0.572 $°$C

4. -0.572 $°$C

An increase in equivalent conductance of a strong electrolyte with dilution is mainly due

to

1. increase in ionic mobility of ions

2. 100% ionisation of electrolyte at normal dilution

3. increase in both, i.e. number of ions and ionic mobility of ions

4. increase in number of ions

The equivalent conductance of M/32 solution of a weak monobasic acid is 8.0 mho cm² and at infinite

dilution is 400 mho cm² .The dissociation constant of this acid is.

1. 1.25x10^-5

2. 1.25x10^-6

3. 6.25x10^-4

4. 1.25x10^-4

A 0.0020 m aqueous solution of an ionic compound Co(NH₃)₅(NO₂)Cl freezes at -0.00732°C. Number of moles of ions which 1 mol of ionic compound produces on being dissolved in water will be (k_f=-1.86^$°$C/ m)

1. 2

2. 3

3. 4

4. 1

Kohlrausch's law states that at

(1) finite dilution, each ion makes definite contribution to equivalent conductance of an electrolyte, whatever be the nature of the other ion of the electrolyte.

(2) infinite dilution, each ion makes definite contribution to equivalent conductance of an electrolyte depending on the nature of the other ion of th electrolyte.

(3) infinite dilution, each ion makes definite contribution to conductance of an electrolyte whatever be the nature of the other ion of the electrolyte.

(4) infinite dilution, each ion makes definite contribution to equivalent conductance of an electrolyte, whatever be the nature of the other ion of the electrolyte.

0.5 molal aqueous solution of a weak acid (HX) is 20% ionised. If K_f for water is 1.86 K kg mol^-1, the lowering in freezing point of the solution is:

(1) -1.12 K

(2) 0.56 K

(3) 1.12 K

(4) - 0.56 K

 A solution containing 10 g per dm³ of urea (molecular mass = 60 g mol^-1) is isotonic with a 5% solution of a non-volatile solute. The molecular mass of this non-volatile solute is:

(1) 250 g mol^-1               

(2) 300 g mol^-1

(3) 350 g mol^-1               

(4) 200 g mol^-1