20 % of acetic acid is dissociated when its 5 g is added to 500 mL of water. The depression in freezing point of such water is × 10-3 ° C. Atomic mass of C , H and O are 12,1 and 16 a.m.u. respectively. [Given: Molal depression constant and density of water are 1.86 K kg mol -1 and 1 g cm -3 respectively.

Question

20 % of acetic acid is dissociated when its 5 g is added to 500 mL of water. The depression in freezing point of such water is × 10-3 ° C. Atomic mass of C , H and O are 12,1 and 16 a.m.u. respectively. [Given: Molal depression constant and density of water are 1.86 K kg mol -1 and 1 g cm -3 respectively. (A)  (B)  (C)  (D)

Tardigrade Admin · Accepted Answer

i =1+( n -1) α ( i =1+0.2(2-1)=1.2 Δ T f = i K f m Δ T f =1.2 × 1.86 × (5 × 1000/60 × 500) Δ t f =3.72 Δ T f =372 × 10-2

i=1+(n−1)α (i=1+0.2(2−1)=1.2 ΔTf​=iKf​m ΔTf​=1.2×1.86×60×5005×1000​ Δtf​=3.72 ΔTf​=372×10−2

$i = 1 + (n - 1) α$
$(i = 1 + 0.2 (2 - 1) = 1.2$
$Δ T_{f} = i K_{f} m$
$Δ T_{f} = 1.2 \times 1.86 \times \frac{5 \times 1000}{60 \times 500}$
$Δ t_{f} = 3.72$
$Δ T_{f} = 372 \times 1 0^{- 2}$