Question

The lowering in vapour pressure is maximum for:

• A. 0.1 M urea
• B. 0.1 M NaCl
• C. 0.1 M MgCl
• D. 0.1 M $K_4\left[Fe\right(CN{)}_6]$

Answer 1

The correct option is D 0.1 M $K_4\left[Fe\right(CN{)}_6]$

The lowering in vapour pressure is maximum for 0.1 M $K_4\left[Fe\right(CN{)}_6]$.

All the given solutions have the same molarity. For 0.1 M $K_4\left[Fe\right(CN{)}_6]$ solution, the dissociation of one molecule of $K_4\left[Fe\right(CN{)}_6]$ gives the maximum number of ions, (5 ions).

$K_4\left[Fe\right(CN{)}_6]\to 4K^{+}+[Fe(CN{)}_6{]}^{4-}$

The lowering in vapour pressure is a colligative property and depends on the number of solute particles.