Question

Select the set having incorrect statements given here.
(i) Manganese exhibits +7 oxidation state
(ii) Zinc forms coloured ions
(iii) $\left[\right.\text{Co}\text{F}_{6}\left]\right.^{3 -}$ is diamagnetic
(iv) Sc forms +4 oxidation state
(v) Zn exhibits only +2 oxidation state

• A. (i), (ii) and (iii)
• B. (ii), (iii) and (iv)
• C. (i), (iii) and (iv)
• D. (i), (iii) and (v)

Answer 1

Answer: (B)

Outer electronic configuration of Mn is $\text{3}\text{d}^{5}\text{4}\text{s}^{2}$ which means it can show +7 oxidation state also (correct)
Zinc does not form coloured ions as it has completely filled $\text{3}\text{d}^{10}\text{4}\text{s}^{2}$ configuration.
In $\left[\right.\text{Co}\text{F}_{6}\left]\right.^{3 -},\text{C}\text{o}^{3 +}$ is a $d^{6}$ system. Fluoride is a weak field ligand and hence it can not cause pairing of electrons.

Sc can show a maximum of +3 oxidation state as it has an outer electronic configuration of $\text{3}\text{d}^{1}\text{4}\text{s}^{2}$ .
Zn exhibits only +2 oxidation state as this oxidation state is the most stable one for it.
Hence (ii), (iii), (iv) are incorrect while (i), (v) are correct.