The freezing point depression constant for water is -1.86° Cm-1. If 5.00 g Na2SO4 is dissolved in 45.0 g H2O, the freezing point is changed by - 3.82° C. Calculate the Van't Hoff factor for Na2SO4.

Question

The freezing point depression constant for water is -1.86° Cm-1. If 5.00 g Na2SO4 is dissolved in 45.0 g H2O, the freezing point is changed by - 3.82° C. Calculate the Van't Hoff factor for Na2SO4. (A) 0.381 (B) 2.05 (C) 2.63 (D) 3.11

Tardigrade Admin · Accepted Answer

Using, Δ T f = i × K f × m i =(Δ T f × W A / K f × n B × 1000) =(3.82 × 45/1.86 ×((5)142) × 1000) =2.63

Q. The freezing point depression constant for water is $- 1.8 6^{\circ} C m^{- 1}$ . If $5.00 g$ $N a_{2} S O_{4}$ is dissolved in $45.0 g$ $H_{2} O$ , the freezing point is changed by $- 3.8 2^{\circ} C$ . Calculate the Van't Hoff factor for $N a_{2} S O_{4}$ .

0.381

2.05

2.63

3.11

Using, $Δ T_{f} = i \times K_{f} \times m$

$i = \frac{Δ T _{f} \times W _{A}}{K _{f} \times n _{B} \times 1000}$

$= \frac{3.82 \times 45}{1.86 \times ( \frac{5}{142} ) \times 1000}$

$= 2.63$

Q. The freezing point depression constant for water is −1.86∘Cm−1. If 5.00g Na2​SO4​ is dissolved in 45.0g H2​O, the freezing point is changed by −3.82∘C. Calculate the Van't Hoff factor for Na2​SO4​.