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 k f =1.86 K kg mol -1 )

Question

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 k f =1.86 K kg mol -1 ) (A) 0.8 (B) 1.1 (C) 1.9 (D) 2.4

Tardigrade Admin · Accepted Answer

[ HCOOH ]=0.5 ml -1 ⇒(0.5 ml × 1.05 g ml -1) HCOOH text in 1 L ⇒ 0.525 g HCOOH in 1 L m =((0.525 / 46)/1 kg ) mol [Assuming dilute solution] ∴ Δ T f = iK f m ⇒ i =(Δ T f / k f m )=(0.0405 × 46/1.86 × 0.525)=1.9

Q. The depression in freezing point observed for a formic acid solution of concentration $0.5 m L L^{- 1}$ is $0.040 5^{\circ} C$ . 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 $k_{f} = 1.86 K k g m o l^{- 1}$ )

$0.8$

$1.1$

$1.9$

$2.4$

Q. The depression in freezing point observed for a formic acid solution of concentration 0.5mLL−1 is 0.0405∘C. Density of formic acid is 1.05gmL−1. The Van't Hoff factor of the formic acid solution is nearly : (Given for water kf​=1.86Kkgmol−1 )

0.8

1.1

1.9

2.4

[HCOOH]=0.5ml−1 ⇒(0.5ml×1.05gml−1)HCOOH in 1L ⇒0.525gHCOOH in 1L m=1kg(0.525/46)​mol [Assuming dilute solution] ∴ΔTf​=iKf​m⇒i=kf​mΔTf​​=1.86×0.5250.0405×46​=1.9

Q. The depression in freezing point observed for a formic acid solution of concentration $0.5 m L L^{- 1}$ is $0.040 5^{\circ} C$ . 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 $k_{f} = 1.86 K k g m o l^{- 1}$ )

$0.8$

$1.1$

$1.9$

$2.4$