Question

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

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

Answer 1

Answer: (D)

${\left({\left(\Delta T\right)}_b\right)}_x>{\left({\left(\Delta T\right)}_b\right)}_y$
same solvent so, $K_b$ is same
$m$ is same (given)
$i_x\cdot k_b\cdot m>i_y\cdot k_b\cdot m\Rightarrow i_x>i_y$
so, $x$ is undergoing dissociation in water.