0.5 Molal aqueous solution of aweak acid (HX) is 20% ionised. If K_f for water is1.86 K kg mol^-1, the lowering in freezing point of the solution is:

• -1.12 K 

• 0.56 K 

• 1.12 K 

• -0.56 K 

C.

1.12 K 

1.00 g of a non- electrolyte solute (molar mass 250 g mol^-1) 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:

• 0.4 K

• 0.3 K

• 0.5 K

• 0.2 K

200 mL of an aqueous solution of a protein contains its 1.26 g . The osmotic pressure of this solution at 300 K is found to be  2.57 x 10^-3 bar. The molar mass of protein will be (R = 0.083 L bar mol^-1 K^-1)

• 51022 g mol^-1

• 122044 g mol^-1

• 31011 g mol^-1

• 61038 g mol^-1

D.

61038 g mol^-1

25.3 g of sodium carbonate, Na₂CO₃ is dissolved in enough water to make 250 mL of solution. If sodium carbonate dissociates completely molar concentration of sodium ion, Na⁺ and carbonate ion, CO₃^2- are respectively (Molar mass of Na₂CO₃ = 106 g mol^-1)

• 0.955 M and 1.910 M

• 1.910 M and 0.955 M 

• 1.90 M and 1.910 M 

• 0.477 M and 0.477 M 

B.

1.910 M and 0.955 M 

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

• 2

• 3

• 4

• 1