CBSE 2023 · Region 1 · Set 1 · Q34 · 5 marks
Assign reason for each of the following:(i)Manganese exhibits the highest oxidation state of+$\displaystyle 7$ among the 3d series of transition elements.(ii)Transition metals and their compounds are generally found to be good catalysts in chemical reactions.(iii)$\displaystyle \mathrm{Cr}^{2+}$ is reducing in nature while with the same d-orbital configuration $\displaystyle \left(\mathrm{d}^{4}\right) \mathrm{Mn}^{3+}$ is an oxidising agent.(iv)Zn has lowest enthalpy of atomization.(v)$\displaystyle \mathrm{Cu}^{+}$is unstable in an aqueous solution.
Assign reason for each of the following:
(i)
Manganese exhibits the highest oxidation state of+$\displaystyle 7$ among the 3d series of transition elements.
(ii)
Transition metals and their compounds are generally found to be good catalysts in chemical reactions.
(iii)
$\displaystyle \mathrm{Cr}^{2+}$ is reducing in nature while with the same d-orbital configuration $\displaystyle \left(\mathrm{d}^{4}\right) \mathrm{Mn}^{3+}$ is an oxidising agent.
(iv)
Zn has lowest enthalpy of atomization.
(v)
$\displaystyle \mathrm{Cu}^{+}$is unstable in an aqueous solution.
Marking-scheme solution
(i) Due to the participation of all 3d and 4s electrons in bond formation /due to the presence of maximum number of unpaired electrons.
(ii) Due to variable oxidation state / due to the ability to adopt multiple oxidation states / due to the large surface area / due to complex formation.
(iii) \(\displaystyle \mathrm{Cr}^{2+}\) changes from \(\displaystyle \mathrm{d}^{4}\) to stable half-filled \(\displaystyle \mathrm{t}_{2 \mathrm{~g}}{ }^{3}\) configuration while \(\displaystyle \mathrm{Mn}^{3+}\) changes to stable half-filled \(\displaystyle \mathrm{d}^{5}\) configuration.
(iv) Due to the absence of unpaired electrons and weak interatomic interactions.
(v) \(\displaystyle \mathrm{Cu}^{+}\)ion (aq.) undergoes disproportionation to \(\displaystyle \mathrm{Cu}^{2+}\) (aq.) and Cu /
\[2 \mathrm{Cu}^{+} \text {(aq.) ⟶ } \mathrm{Cu}^{2+} \text { (aq.) + } \mathrm{Cu}(\mathrm{~s})
\]
The d-and f-Block ElementsGeneral Properties of the Transition Elements (d-Block)Understandlong_answermedium
More from The d-and f-Block Elements
- (i) Silver atom has completely filled d-orbitals in its ground state, it is still considered to be a…2022 · asked 3×
- (i) Describe giving reason which one of the following pairs has the property indicated: (I) Fe or Cu - higher…2026 · asked 3×
- The diamagnetic species is:2025 · asked 3×
- Assertion: Zr and Hf are of almost similar atomic radii. Reason (R): This is due to Lanthanoid contraction.2024 · asked 3×
- (i) When pyrolusite ore is fused with KOH, in presence of air, a dark green coloured product 'A' is obtained…2025 · asked 3×
- The element having [Ar] 3 d^10 4 s^1 electronic configuration is2025 · asked 3×
- From the given E^ values of the first row transition elements, answer the following questions: (i) Why is E…2022 · asked 3×
- Account for the following: (i) Transition metals and their compounds show catalytic activities. (ii) Zn, Cd…2022 · asked 3×
CBSE Class 12 Chemistry past-paper question from the 2023board exam, with the answer as CBSE’s own marking scheme gives it. Where our answers come from.