The freezing point depression constant for water is $–1.86\;Cm^{–1}$. If $5.00 \;g$ $Na_2SO_4$ is dissolved in $45.0g\; H_2O$, the freezing point is changed by $–3.82^o C$. Calculate the Van't Hoff factor for $Na_2SO_4$

Question

( A ) 2.63
( B ) 2.05
( C ) 3.11
( D ) 0.381