To solve this problem, we need to understand the concept of boiling point elevation, which is a colligative property.$\\$Colligative properties depend on the number of solute particles in a solution, not on the identity of the solute.$\\$The boiling point elevation $(\Delta T_b)$ is given by:$\\ \Delta T_b = i \cdot K_b \cdot m \\$where:$\\$• $i$ is the van 't Hoff factor, representing the number of particles the solute splits into.$\\$• $K_b$ is the ebullioscopic constant of the solvent (water in this case).$\\$• $m$ is the molality of the solution.$\\$Given that the boiling point of the solution of X is greater than that of Y,$\\ \Delta T_{b,\ X} > \Delta T_{b,\ Y} \\$Since both solutions are equimolal (same molality), the difference in boiling point elevation must be due to the $i$ factor.$\\$This implies:$\\ i_X \cdot K_b \cdot m > i_Y \cdot K_b \cdot m \\$Simplifying, we get:$\\ i_X > i_Y \\$This means that X dissociates into more particles than Y in the solution.$\\$Now, let's analyze the options:$\\$• Option 1: Molecular mass of X is greater than the molecular mass of Y.$\\$• Option 2: Molecular mass of X is less than the molecular mass of Y.$\\$• Option 3: Y is undergoing dissociation in water while X undergoes no change.$\\$• Option 4: X is undergoing dissociation in water.$\\$Since $i_X > i_Y,$ X must be undergoing dissociation in water, leading to a higher boiling point elevation.$\\$Therefore, the correct option is Option 4: X is undergoing dissociation in water.