Skip to content

In case of association… (Class 12 Chemistry 2025, Q1)

questionbuddy.in/q/cbse-12-chemistry-2025-56-1-1-q1-association-abnormal-molar-mass-solute

ChemistryCBSE Class 12 · Board exam 2025, set 56/1/1 · 1 mark · MCQ

CBSE Class 12 Chemistry 2025: question 1

Set in the CBSE Class 12 board exam of 2025, paper 56/1/1, section A, question 1, for 1 mark. Try it first; the hints and our step-by-step solution are below.

Q1 · 1 mark · MCQSolutions

In case of association, abnormal molar mass of solute will

  1. (A)increase
  2. (B)decrease
  3. (C)remain same
  4. (D)first increase and then decrease

Source: official question paper from cbse.gov.in (PDF). See it in the full 2025 board paper, set 56/1/1.

Hints

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

Hint 1

Ask whether association raises or lowers the number of solute particles.

Hint 2

Molar mass found from a colligative property is inversely proportional to that property.

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. On association, solute particles combine into one, so the number of particles falls and every colligative property comes out lower than expected ().

  2. Molar mass is inversely proportional to the colligative property, so the observed (abnormal) molar mass is greater than the true value. It increases: option (A).

    1 mark

Answer: Increase, option (A)

Where the marks are

  • Chooses (A) increase (1 mark)

Revise the chapter

Practise this chapterBoard-style questions from Solutions, one at a time, marked against the answer key and marking points.Back to the full paper2025 board paper, set 56/1/1: 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.