Question

The boiling point of 0.2 mol $k{g}^{-1}$ solution of X in water is greater than equimolal solution of Y in water. Which one of the following statements is true in this case?

• A. Molecular mass of X is less than the molecular mass of Y
• B. Y is undergoing dissociation in water while X undergoes no change
• C. X is undergoing dissociation in water
• D. Molecular mass of X is greater than the molecular mass of Y

Answer 1

Answer: (C)

X is undergoing dissociation in water

$\left(\Delta Tb\right)x>\left(\Delta Tb\right)y$

same solvent so, Kb is same

m is same (given)

$ix.kb.m>iy.kb.m$

$\Rightarrow iX>iy$

so, x is undergoing dissociation in water.

Hence, the correct option is $C$