Question

Explain with reason:
(i) Cr²⁺ is a reducing agent while Mn³⁺ is an oxidising agent, while both have d⁴ configuration.

Hint:

A reducing agent donates electrons, while an oxidizing agent accepts electrons. Cr\(^{2+}\) reduces by losing electrons, and Mn\(^{3+}\) oxidizes by accepting electrons.

Answer 1

- Cr\(^{2+}\): The ion Cr\(^{2+}\) has the electron configuration \( [Ar] 3d^4 \). Since Cr\(^{2+}\) can easily lose an electron to become Cr\(^{3+}\), it acts as a reducing agent, facilitating the reduction of other species by donating electrons.
- Mn\(^{3+}\): The ion Mn\(^{3+}\) has the electron configuration \( [Ar] 3d^4 \), which is unstable and readily accepts an electron to stabilize itself as Mn\(^{2+}\). Hence, Mn\(^{3+}\) acts as an oxidizing agent, accepting electrons from other species.