Write the IUPAC names of the following coordination compounds (any three) : (a) [Co(NH_3)_4Cl(NO_2)]Cl (b) [Ni(NH_3)_6]Cl_2 (c) K_3[Cr(C_2O_4)_3] (d) [Co(en)_2Br_2]^+

ChemistryCBSE Class 12 · Board exam 2024, set 56/5/1 · 3 marks · Short answer

CBSE Class 12 Chemistry 2024: question 22

Set in the CBSE Class 12 board exam of 2024, paper 56/5/1, section C, question 22, for 3 marks. Try it first; the hints and our step-by-step solution are below.

Q22 · 3 marks · Short answerCoordination Compounds

Write the IUPAC names of the following coordination compounds (any three) :

(a)
$[Co (N H_{3})_{4} Cl (N O_{2})] Cl$
1 mark
(b)
$[Ni (N H_{3})_{6}] C l_{2}$
1 mark
(c)
$K_{3} [Cr (C_{2} O_{4})_{3}]$
1 mark
(d)
$[Co (en)_{2} B r_{2}]^{+}$
1 mark

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

Name ligands in alphabetical order before the metal, and put the oxidation state in Roman numerals.

Hint 2

In an anionic complex the metal name ends in '-ate'; find the oxidation state from the charge balance.

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.

(a) $[C o (N H_{3})_{4} C l (N O_{2})] C l$ : Tetraamminechloridonitrito-N-cobalt(III) chloride
1 mark
(b) $[N i (N H_{3})_{6}] C l_{2}$ : Hexaamminenickel(II) chloride
1 mark
(c) $K_{3} [C r (C_{2} O_{4})_{3}]$ : Potassium trioxalatochromate(III)
1 mark
(d) $[C o (e n)_{2} B r_{2}]^{+}$ : Dibromidobis(ethane-1,2-diamine)cobalt(III) ion. This is an alternative part; any three correct names earn the full 3 marks.

Answer: (a) Tetraamminechloridonitrito-N-cobalt(III) chloride; (b) Hexaamminenickel(II) chloride; (c) Potassium trioxalatochromate(III); (d) Dibromidobis(ethane-1,2-diamine)cobalt(III) ion

Where the marks are

Each correct IUPAC name, any three (1 × 3 marks)

Revise the chapter

Chapter: Coordination Compounds (notes, formulas, where marks are lost and every past question)
Topic: IUPAC Nomenclature of Coordination Compounds

Practise this chapterBoard-style questions from Coordination Compounds, 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 22

Hints

Step-by-step solution

Revise the chapter

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