Y is undergoing dissociation in water while X undergoes no change
Molecular mass of X is less than the molecular mass of Y
Molecular mass of X is greater than the molecular mass of Y
X is undergoing dissociation in water
(ΔTb)x > (ΔTb)y
Same solvent so, Kb is same
m is same (given)
ix.Kb.m > iy.Kb.m
⇒ix > iy
So, X is undergoing dissociation in water.
Hence, the correct option is D