An aqueous 0.050 m solution of Na2SO4 freezes at -0.270 degC (K_f = 1.86, K_b = 0.52 K kg mol^-1; i = 1 + 2alpha). Which of the following statements is/are correct?

The degree of dissociation is 0.95.

The total molality of solute particles is 0.145 mol kg^-1.

The degree of dissociation is 0.95.

The total molality of solute particles is 0.145 mol kg^-1.

The solution boils at 100.15 degC at 1 atm.

JEE Advanced levelOne or more correct optionsDifficulty 3 of 3so110

An aqueous $0.050 m$ solution of $Na X_{2} SO X_{4}$ freezes at $- 0.270^{\circ} C$ ( $K_{f} = 1.86$ , $K_{b} = 0.52 K kg mo l^{- 1}$ ; $i = 1 + 2 α$ ). Which of the following statements is/are correct?

i = 0.270/ (1.86 \times 0.050) = 2.903

;

α = (2.903 - 1) /2 = 0.952

; particle molality

= im = 0.1452 mol k g^{- 1}

. The boiling point elevation is only

Δ T_{b} = 2.903 \times 0.52 \times 0.050 = 0.0755 K

, so the boiling point is about

100.08^{\circ} C

, not

100.15^{\circ} C