JEE Main · 2019 · Shift-IeasySOL-010

A solution of sodium sulphate contains 92 g of Na+ ions per kilogram of water. The molality of Na+ ions in that…

Solutions · Class 12 · JEE Main Previous Year Question

Question

A solution of sodium sulphate contains 92 g of Na+\mathrm{Na^+} ions per kilogram of water. The molality of Na+\mathrm{Na^+} ions in that solution in mol kg⁻¹ is:

Options
  1. a

    16

  2. b

    4

  3. c

    12

  4. d

    8

Correct Answerb

4

Detailed Solution

Strategy:\n> Molality of ions is calculated as moles of that specific ion per kg of solvent.\n\nStep 1: Calculate moles of } \ce{Na+} \text{\nMass = 92 g. Atomic mass = 23.\nn=92/23=4textmoln = 92 / 23 = 4\\text{ mol}\n\nStep 2: Calculate molality\nSolvent mass = 1 kg.\nm=4/1=4textmol/kgm = 4 / 1 = 4\\text{ mol/kg}\n\ntextAnswer:(2)\boxed{\\text{Answer: (2)}}

Practice this question with progress tracking

Want timed practice with adaptive difficulty? Solve this question (and hundreds more from Solutions) inside The Crucible, our adaptive practice platform.

A solution of sodium sulphate contains 92 g of Na+ ions per kilogram of water. The molality of Na+… (JEE Main 2019) | Canvas Classes