CBSE Class 12 Chemistry sample paper 2026-27: question 9
From the official CBSE sample question paper for 2026-27, section A, question 9, for 1 mark. Try it first; the hints and our step-by-step solution are below.
Q9 · 1 mark · MCQThe d- and f-Block Elements
Which one of the following element will be strong oxidising agent in their +3 oxidation state? (Atomic no. Cr=24, Mn=25, Ti=22, Fe=26)
- (A)Cr
- (B)Mn
- (C)Ti
- (D)Fe
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
Write the d-electron configuration of each M³⁺ and of the M²⁺ it would form.
Hint 2
Look for an M²⁺ ion with a half-filled d subshell.
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.
() readily gains an electron to form , which has the extra-stable half-filled configuration.
- 1 mark
Its high V makes it a strong oxidising agent. So the answer is Mn.
Answer: Option (B) Mn
Where the marks are
- Mn³⁺ is reduced to stable d⁵ Mn²⁺, so it is a strong oxidant (1 mark)
Revise the chapter
- Chapter: The d- and f-Block Elements (notes, formulas, where marks are lost and every past question)
- Topic: Oxidation States and Electrode Potentials of Transition Metals
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