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(i) Give a chemical test… (Class 12 Chemistry 2026, Q19b)

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

CBSE Class 12 Chemistry 2026: question 19(b)

Set in the CBSE Class 12 board exam of 2026, paper 56/1/1, section B, question 19(b), for 2 marks. Try it first; the hints and our step-by-step solution are below.

Q19(b) · 2 marks · Very short answerCoordination Compounds

(i) Give a chemical test to show that and are ionisation isomers.
(ii) What is meant by the 'Chelate effect' ? Give an example.

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

Hints

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

Hint 1

Which ion lies outside the coordination sphere in each compound?

Hint 2

Ions outside the bracket are free in solution; think of a reagent that precipitates Cl⁻ or SO₄²⁻.

Hint 3

For the chelate effect, think of ethylenediamine forming a ring with the metal.

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. (i) Add solution to aqueous solutions of each compound:

    • gives free ions, so a white precipitate of AgCl forms.
    • has its Cl inside the coordination sphere, so there is no precipitate.

    Conversely, gives a white precipitate of only with . Different ions are released in solution, which proves the two are ionisation isomers.

    1 mark

  2. (ii) Chelate effect: a di- or polydentate ligand binding a single metal ion through two or more donor atoms forms a ring (chelate). Such complexes are more stable than similar complexes of monodentate ligands.

    ½ mark

  3. Example: is more stable than .

    ½ mark

Answer: (i) AgNO₃ gives a white AgCl precipitate only with [Co(NH₃)₅SO₄]Cl (BaCl₂ gives BaSO₄ only with [Co(NH₃)₅Cl]SO₄); (ii) extra stability of complexes formed by chelating ligands, e.g. [Co(en)₃]³⁺.

Where the marks are

  • Correct chemical test with observation for both compounds (1 mark)
  • Definition of chelate effect (½ mark)
  • Correct example (½ 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 paper2026 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.