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Which of the following… (Class 12 Chemistry 2023, Q21a)

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ChemistryCBSE Class 12 · Board exam 2023, set 56/5/1 · 2 marks · Very short answer

CBSE Class 12 Chemistry 2023: question 21(a)

Set in the CBSE Class 12 board exam of 2023, paper 56/5/1, section B, question 21(a), for 2 marks. Try it first; the hints and our step-by-step solution are below.

Q21(a) · 2 marks · Very short answerCoordination Compounds

Which of the following species cannot act as a ligand ? Give reason.
, , ,

Source: official question paper from cbse.gov.in (PDF). See it in the full 2023 board paper, set 56/5/1.

Hints

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

Hint 1

A ligand donates an electron pair to the central metal atom.

Hint 2

Check which species has used up all lone pairs on its donor atom.

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. cannot act as a ligand.

    1 mark

  2. Reason: a ligand must donate a lone pair to the metal (Lewis base). In the lone pair of N is already used in forming the fourth N–H bond, so no lone pair is available for donation. , and all have lone pairs.

    1 mark

Answer: — it has no lone pair of electrons

Where the marks are

  • Identifies (1 mark)
  • Reason: no lone pair available / cannot act as Lewis base (1 mark)

Revise the chapter

Practise this chapterBoard-style questions from Coordination Compounds, one at a time, marked against the answer key and marking points.Back to the full paper2023 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.