Q51 · CSIR NET Chemistry, December 2015
Paper: CSIR NET December 2015 · Subject: Inorganic Chemistry · Chapter: Coordination Chemistry · Topic: Coordination Chemistry – General · Marks: 2 · Difficulty: Easy
The oxidizing power of $\left[\mathrm{CrO}_{4}\right]^{2-},\left[\mathrm{MnO}_{4}\right]^{2-}$ and $\left[\mathrm{FeO}_{4}\right]^{2-}$ follows the order
(a)$\left[\mathrm{CrO}_{4}\right]^{2-}<\left[\mathrm{MnO}_{4}\right]^{2-}<\left[\mathrm{FeO}_{4}\right]^{2-}$
(b)$\left[\mathrm{FeO}_{4}\right]^{2-}<\left[\mathrm{MnO}_{4}\right]^{2-}<\left[\mathrm{CrO}_{4}\right]^{2-}$
(c)$\left[\mathrm{MnO}_{4}\right]^{2-}<\left[\mathrm{FeO}_{4}\right]^{2-}<\left[\mathrm{CrO}_{4}\right]^{2-}$
(d)$\left[\mathrm{CrO}_{4}\right]^{2-}<\left[\mathrm{FeO}_{4}\right]^{2-}<\left[\mathrm{MnO}_{4}\right]^{2-}$
Answer
Answer: A ✓ checked by 4AB · confidence high
Explanation
The +6 state becomes less stable (more oxidising) from Cr to Fe: CrO₄²⁻ < MnO₄²⁻ < FeO₄²⁻.
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