The depression in freezing point observed for a formic acid solution of concentration 0-5 mL L-1 is 0-0405- C- Density of formic acid is 1-05 g mL-1- The Van-t Hoff factor of the formic acid solution is nearly Given for water kf-1-86 K kg mol-1

Δ T_f nbsp; nbsp;of formic acid = 0.0405^∘ C Concentration = 0.5 mL/L and density = 1.05 g/mL ∴ nbsp;Mass of formic acid in solution = 1.05 × 0.5 g =0. ...

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Standard XII

Chemistry

Van't Hoff Factor

The depressio...

Question

The depression in freezing point observed for a formic acid solution of concentration $0.5 m L L^{- 1}$ is ${0.0405}^{\circ} C$ . Density of formic acid is $1.05 g m L^{- 1}$ . The Van’t Hoff factor of the formic acid solution is nearly
(Given for water $k_{f} = 1.86 K k g m o l^{- 1}$ )

1.9

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Solution

The correct option is A $1.9$
$Δ T_{f}$ of formic acid $= {0.0405}^{\circ} C$
Concentration $= 0.5 m L / L$
and density $= 1.05 g / m L$
$∴$ Mass of formic acid in solution $= 1.05 \times 0.5 g$
$= 0.525 g$
$∴$ According to Van’t Hoff equation,
$Δ T_{f} = i k_{f} . m$
$0.0405 = i \times 1.86 \times \frac{0.525}{46 \times 1}$
(Assuming mass of $1 L$ water $= k g$ )
$i = \frac{0.0405 \times 46}{1.86 \times 0.525} = 1.89 \approx 1.9$

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The depression in freezing point observed for a formic acid solution of concentration 0.5 mL L–1 is 0.0405∘C. Density of formic acid is 1.05 g mL–1. The Van’t Hoff factor of the formic acid solution is nearly (Given for water kf=1.86 K kg mol−1)

The depression in freezing point observed for a formic acid solution of concentration $0.5 m L L^{- 1}$ is ${0.0405}^{\circ} C$ . Density of formic acid is $1.05 g m L^{- 1}$ . The Van’t Hoff factor of the formic acid solution is nearly
(Given for water $k_{f} = 1.86 K k g m o l^{- 1}$ )