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A. Write the IUPAC… (Class 12 Chemistry SQP 2024-25, Q18)

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ChemistryCBSE Class 12 · Sample paper, session 2024-25 · 2 marks · Very short answer

CBSE Class 12 Chemistry sample paper 2024-25: question 18

From the official CBSE sample question paper for 2024-25, section B, question 18, for 2 marks. Try it first; the hints and our step-by-step solution are below.

Q18 · 2 marks · Very short answerCoordination Compounds

a. Write the IUPAC name of the following complex: (1)
b. Name the metal present in the complex compound of
(i) Haemoglobin (ii) Vitamin B-12 (½+½)

Source: official sample paper from cbseacademic.nic.in (PDF). See it in the full Sample paper 2024-25.

Hints

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

Hint 1

Work out the oxidation state of chromium first.

Hint 2

The complex ion is an anion, so how does the metal name end?

Hint 3

Haemoglobin carries O₂ through an Fe-porphyrin; B-12 is also called cobalamin.

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. (a) Find the oxidation state of Cr: , so . Name the ligands alphabetically (aqua before oxalato). Name the anionic complex with the suffix '-ate' and add the water of crystallisation.

  2. IUPAC name: Potassium diaquadioxalatochromate(III) hydrate (monohydrate).

    1 mark

  3. (b) (i) Haemoglobin contains iron (Fe).

    ½ mark

  4. (ii) Vitamin B-12 (cyanocobalamin) contains cobalt (Co).

    ½ mark

Answer: (a) Potassium diaquadioxalatochromate(III) hydrate; (b) (i) Iron (ii) Cobalt

Where the marks are

  • Correct IUPAC name with Cr(III) and -ate ending (1 mark)
  • Haemoglobin: iron (½ mark)
  • Vitamin B-12: cobalt (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 paperSample paper 2024-25: 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.