Q 1 :    

We have three aqueous solutions of NaCl labelled as ‘A’, ‘B’ and ‘C’ with concentration 0.1 M, 0.01 M and 0.001 M, respectively. The value of van’t Hoff factor (i) for these solutions will be in the order:                     [2024]

• ${\mathrm{i}}_{\mathrm{A}}<{\mathrm{i}}_{\mathrm{B}}<{\mathrm{i}}_{\mathrm{C}}$

   

• ${\mathrm{i}}_{\mathrm{A}}<{\mathrm{i}}_{\mathrm{C}}<{\mathrm{i}}_{\mathrm{B}}$

   

• ${\mathrm{i}}_{\mathrm{A}}={\mathrm{i}}_{\mathrm{B}}={\mathrm{i}}_{\mathrm{C}}$

   

• ${\mathrm{i}}_{\mathrm{A}}>{\mathrm{i}}_{\mathrm{B}}>{\mathrm{i}}_{\mathrm{C}}$

   

Q 2 :    

A solution containing 10 g of an electrolyte ${\mathrm{AB}}_2$ in 100 g of water boils at 100.52${}^{°}\mathrm{C}$. The degree of ionization of the electrolyte ($\alpha$) is _____$\times {10}^{-1}$. (nearest integer)

 

[Given : Molar mass of ${\mathrm{AB}}_2=200\mathrm{g}$ ${\mathrm{mol}}^{-1}$. ${\mathrm{K}}_{\mathrm{b}}$ (molal boiling point elevation const. of water) = 0.52 K kg ${\mathrm{mol}}^{-1}$, boiling point of water = 100°C; ${\mathrm{AB}}_2$ ionises as ${\text{AB}}_2\to {\text{A}}^{2+}+2{\text{B}}^{-}$]                [2024]