Question

Out of $1M$ urea solution and $1MKCl$ solution, which one has higher freezing point ?

Answer 1

Freezing point depends on Van't Hoff factor $\left(i\right)$.

Van't Hoff factor for $KCl=2$

Van't Hoff factor for urea $=1$

$\because i_{KCl}>i_{\text{urea}}$

Thus $KCl$ has highest freezing point.