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

1.00 g of a non-electrolyte solute (molar mass 250g/mol) was dissolved in 51.2 g of benzene. If the freezing point depression constant, K_f of benzene is 5.12 K kg mol^-1, the freezing point of benzene will be lowered by:-

(1) 0.4 K

(2) 0.3 K

(3) 0.5 K

(4) 0.2 K

A solution of acetone in ethanol:

1. Shows a negative deviation from Raoult's law.

2. Shows a positive deviation from Raoult's law.

3. Behaves like a near ideal solution.

4. Obeys Raoult's law.

Three solutions are prepared by adding 'w' gm of 'A' into 1kg of water, 'w' gm of 'B' into another 1 kg of water and 'w' gm of 'C' in another 1 kg of water (A, B, C are non electrolytic). Dry air is passed from these solutions in sequence (A → B → C). The loss in weight of solution A was found to be 2gm while solution B gained 0.5 gm and solution C lost 1 gm. Then the relation between molar masses of A, B and C is :

(1) MA: M_B : Mc = 4 : 3 : 5

(2) M_A : M_B: M_c = $\frac{1}{4}:\frac{1}{3}:\frac{1}{5}$

(3) Mc > MA > MB

(4) MB > M_A> M_c

How many mili moles of sucrose should be dissolved in 500 gms of water so as to get a solution which has a difference of 103.57°C between boiling point and freezing point.

(K₁ = 1.86 K Kg mol⁻¹, K_b = 0.52 K Kg mo1⁻¹)

(1) 500 mmoles

(2) 900 mmoles

(3) 750 mmoles

(4) 650 mmoles

The molar heat of vapourization of toluene is AHv. If its vapour pressure at 315 K is 60 torr & that at 356K is300 torr then AHv = ? (log 2 = 0.3)

(1) 37.5 kJ/mole

(2) 3.75 kJ/mole

(3) 37.5 J/mol

(4) 3.75 J/mole

Relative decrease in vapour pressure of an aqueous solution containing 2 moles [Cu(NH₃)₃Cl) Cl in 3 moles H₂O is 0.50. On reaction with AgNO₃, this solution will form (assuming no change in degree of ionisation of substance on adding AgNO₃)

1. 1 mol AgCl

2. 0.25 mol AgCl

3. 0.5 mol AgCl

4. 0.40 mol AgCl