Molarity (M) is defined as number of moles of solute dissolved in:
Answer & explanation
Correct answer: option 1
The correct answer is Option (1) → One cubic decimeter of solution
Molarity refers to the volume of the solution (one litre, that is one cubic decimetre), not of the solvent.
Why the other options are incorrect
Option (2) One cubic decimeter of solvent — Incorrect. Molarity refers to the volume of the whole solution, not of the solvent alone.
Option (3) One mole of solvent — Incorrect. Moles of solute per mole of solution relates to mole fraction, not molarity.
Option (4) One molal solution — Incorrect. Molality is a separate unit (moles per kilogram of solvent); it is not the reference quantity in molarity.
NCERT (2026-27 edition):
Molarity
