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The boiling points… (Class 12 Chemistry SQP 2026-27, Q1)

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ChemistryCBSE Class 12 · Sample paper, session 2026-27 · 1 mark · MCQ

CBSE Class 12 Chemistry sample paper 2026-27: question 1

From the official CBSE sample question paper for 2026-27, section A, question 1, for 1 mark. Try it first; the hints and our step-by-step solution are below.

Q1 · 1 mark · MCQCompetency-basedAmines

The boiling points and values of isomeric amines are given in table 1.

AmineBoiling point/KpKb (approx)
P329.33.00
Q310.59.83
R350.83.22

Table 1

Which one of the following statement is correct?

  1. (A)Amine P is more volatile than amine R, but less basic
  2. (B)Amine R will give white precipitate with Hinsberg reagent, which is soluble in NaOH
  3. (C)Amine Q is more soluble in water as compared to R.
  4. (D)Amine P and Q can be prepared by Gabriel Phthalimide process.

Source: official sample paper from cbseacademic.nic.in (PDF). See it in the full Sample paper 2026-27.

Hints

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

Hint 1

Relate boiling point to the number of N–H bonds available for hydrogen bonding.

Hint 2

Recall which class of amine gives a Hinsberg product that is soluble in alkali.

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. Among isomeric amines, H-bonding decides boiling point: primary (two N–H) > secondary (one N–H) > tertiary (none). So R (350.8 K) is primary, P (329.3 K) is secondary and Q (310.5 K) is tertiary.

  2. A primary amine reacts with Hinsberg reagent () to give an N-alkylbenzenesulphonamide. Its N–H is acidic, so the white precipitate dissolves in NaOH. Statement B is therefore correct.

    1 mark

  3. The other statements are wrong. A: P has the lower pKb, so P is more basic than R, not less. C: tertiary Q cannot H-bond as well as R, so it is less soluble in water. D: the Gabriel process gives only primary amines.

Answer: Option (B)

Where the marks are

  • Identifies R as the primary amine and chooses (B) (1 mark)

Revise the chapter

Practise this chapterBoard-style questions from Amines, one at a time, marked against the answer key and marking points.Back to the full paperSample paper 2026-27: 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.