What should be the freezing point of aqueous solution containing 17 g of C2H5OH in 1000 g of water (Kf for water =1.86 deg kg mol-1) ?

Question

What should be the freezing point of aqueous solution containing 17 g of C2H5OH in 1000 g of water (Kf for water =1.86 deg kg mol-1) ? (A) -0.69°C (B) 0.34°C (C) 0.0°C (D) -0.34°C

Tardigrade Admin · Accepted Answer

Δ T=Kf ×(wB×1000/mB× wA) =1.86×(17×1000/46×1000)=0.69 ∴ Freezing point of solution =0-0.69=-0.69°C

Q. What should be the freezing point of aqueous solution containing $17 g$ of $C_{2} H_{5} O H$ in $1000 g$ of water $(K_{f}$ for water $= 1.86 d e g k g m o l^{- 1})$ ?

$- 0.6 9^{\circ} C$

$0.3 4^{\circ} C$

$0. 0^{\circ} C$

$- 0.3 4^{\circ} C$

$Δ T = K_{f} \times \frac{w _{B} \times 1000}{m _{B} \times w _{A}}$
$= 1.86 \times \frac{17 \times 1000}{46 \times 1000} = 0.69$
$∴$ Freezing point of solution $= 0 - 0.69 = - 0.6 9^{\circ} C$

Q. What should be the freezing point of aqueous solution containing 17g of C2​H5​OH in 1000g of water (Kf​ for water =1.86degkgmol−1) ?

−0.69∘C

0.34∘C

0.0∘C

−0.34∘C