Question

Which of the following 0.1 M aqueous solution will have lowest freezing point?

• A. Urea
• B. Glucose
• C. $\text{NaCl}$
• D. $K_{2}S{O}_4$

Answer 1

Answer: (D)

Depression in freezing point depends upon the number of ions present in the compound. ${\text{K}}_{\text{2}}\text{S}{\text{O}}_{\text{4}}$ gives three ions ( $\text{2}{\text{H}}^{+}$ and one ${\text{SO}}_4^{2-}$ ion). While $\text{NaCl}$ gives 2 ions ( $\text{1N}{\text{a}}^{\text{+}}$ and $\text{2C}{\text{l}}^{-}$ ion). Hence, ${\text{K}}_{\text{2}}\text{S}{\text{O}}_{\text{4}}$ will cause maximum depression in freezing point. Therefore, $\text{0}\text{.1}\text{M}{\text{K}}_{\text{2}}\text{S}{\text{O}}_{\text{4}}$ solution will have lowest freezing point.