Van't Hoff factor for Na_2SO_4·10H_2O solution, assuming complete ionization is (A) 1 (B) 3 (C) 13 (D) 2

ChemistryCBSE Class 12 · Board exam 2024, set 56/5/1 · 1 mark · MCQ

CBSE Class 12 Chemistry 2024: question 12

Set in the CBSE Class 12 board exam of 2024, paper 56/5/1, section A, question 12, for 1 mark. Try it first; the hints and our step-by-step solution are below.

Q12 · 1 mark · MCQSolutions

Van't Hoff factor for $N a_{2} S O_{4} \cdot 10 H_{2} O$ solution, assuming complete ionization is

(A)1
(B)3
(C)13
(D)2

Source: official question paper from cbse.gov.in (PDF). See it in the full 2024 board paper, set 56/5/1.

Hints

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

Hint 1

Water of crystallisation does not count as solute particles.

Hint 2

Count the ions that one formula unit of $N a_{2} S O_{4}$ produces.

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.

$N a_{2} S O_{4} \cdot 10 H_{2} O \to 2 N a^{+} + S O_{4}^{2 -} + 10 H_{2} O$ . The water of crystallisation simply becomes part of the solvent.
Three ions are formed, so $i = 3$ . Option (B).
1 mark

Answer: i = 3, option (B)

Where the marks are

Counts the ions formed to get i = 3 (1 mark)

Revise the chapter

Chapter: Solutions (notes, formulas, where marks are lost and every past question)
Topic: Abnormal Molar Mass and van't Hoff Factor

Practise this chapterBoard-style questions from Solutions, one at a time, marked against the answer key and marking points.Back to the full paper2024 board paper, set 56/5/1: every question, by section.

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CBSE Class 12 Chemistry 2024: question 12

Hints

Step-by-step solution

Revise the chapter

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