The elevation in boiling point will be maximum in

The correct answer is Option (2) → 1 molal sodium chloride solution

Elevation of boiling point is a colligative property: it depends on the number of solute particles, not on their nature.

    ΔT_b = i K_b m

For the same solvent (water, same K_b), ΔT_b is largest when the product i × m is largest:

• 1 m glucose (non-electrolyte, i = 1): i × m = 1

• 1 m NaCl (NaCl → \( \ce{Na^{+}} \) + \( \ce{Cl^{-}} \), i = 2): i × m = 2

• 0.1 m glucose (i = 1): i × m = 0.1

• 0.1 m NaCl (i = 2): i × m = 0.2

The 1 molal NaCl solution has the most particles, so its boiling point rises the most.