Skip to content

State Henry’s law… (Class 12 Chemistry 2026, Q17b)

questionbuddy.in/q/cbse-12-chemistry-2026-56-5-1-q17b-henry-law-calculate-mole-fraction

ChemistryCBSE Class 12 · Board exam 2026, set 56/5/1 · 2 marks · Very short answer

CBSE Class 12 Chemistry 2026: question 17(b)

Set in the CBSE Class 12 board exam of 2026, paper 56/5/1, section B, question 17(b), for 2 marks. Try it first; the hints and our step-by-step solution are below.

Q17(b) · 2 marks · Very short answerSolutions

State Henry’s law. Calculate the mole fraction of in water at 298 K under 760 mm Hg.
(Given : for in at 298 K = mm Hg)

Source: official question paper from cbse.gov.in (PDF). See it in the full 2026 board paper, set 56/5/1.

Hints

Open one hint at a time and try again before the next.

Hint 1

Henry's law links the partial pressure of a gas to its mole fraction in solution through .

Hint 2

Rearrange to make the subject.

Step-by-step solution

Each step shows the marks it earns, as an examiner would award them. Checked by an independent re-solve from the question paper.

  1. Henry's law: at a constant temperature, the solubility of a gas in a liquid is directly proportional to the partial pressure of the gas above the liquid. Equivalently, , where is the mole fraction of the gas in solution.

    1 mark

  2. ½ mark

  3. ½ mark

Answer:

Where the marks are

  • Correct statement of Henry's law (1 mark)
  • Uses with correct substitution (½ mark)
  • Gets (½ mark)

Revise the chapter

  • Chapter: Solutions (notes, formulas, where marks are lost and every past question)
Practise this chapterBoard-style questions from Solutions, one at a time, marked against the answer key and marking points.Back to the full paper2026 board paper, set 56/5/1: every question, by section.

The question is transcribed from the official paper; figures are described in words. The solution, hints and chapter tag are ours. Spotted an error? Write tosupport@questionbuddy.in.