KCET 2025 Chemistry Paper

Option A is correct: mole fraction and mass percent (w/w) are both unitless.
Mole fraction
xi=‌

ni

Σjnj

It's simply a ratio of moles, so no units.
Mass percent (w/w)
‌ mass ‌1%=‌

‌ mass of solute ‌

‌ total mass of solution ‌

×100%
Again, a ratio of masses, giving a percentage without units.
By contrast, molality has units of mol/kg and molarity has mol/L, so neither is unitless.