Question

Which of the following equimolar solution have highest vapour pressure?

• A. Glucose
• B. $NaCl$
• C. $K_2{SO}_4$
• D. $K_4{Fe\left(CN\right)}_6$

Answer 1

Answer: (A)

Glucose

Vapour Pressure of equimolar solutions is inversely proportional to no. of particles in solution/ions.

$VP\propto \frac{1}{\text{no.of particles/ions}}$

Since glucose is a non-electrolytes, it cannot dissociate into ions. Hence, the van't Hoff factor of glucose is 1. $(i=1)$

$NaCl\to N{a}^{+}+C{l}^{-}$ $i=2$

$K_{2}S{O}_4\to 2K^{+}+{S{O}_4}^{2-}$ $i=3$

$K_{4}Fe(CN{)}_6\to 4K^{+}+{Fe(CN{)}_6}^{4-}$ $i=5$

Glucose in the equimolar mixture has higher vapour pressure.

Hence, option A is correct.