Question

Each of the following ions contains vanadium in a +5 oxidation state except:

• A. ${\mathrm{VO}}^{2+}$
• B. $\mathrm{V}{\left(\mathrm{OH}\right)}^{4+}$
• C. ${{\mathrm{VO}}_2}^{+1}$
• D. ${\left[{\mathrm{VO}}_3\mathrm{OH}\right]}^{2-}$

Answer 1

The correct option is A

${\mathrm{VO}}^{2+}$

The explanation for the correct option:

The oxidation state: of an atom in a chemical compound provides insight into the number of electrons lost and, therefore, describes the extent of oxidation of the atom.

• The oxidation state of an atom can be defined as the hypothetical charge that would be held by that atom if all of its bonds to other atoms were completely ionic in nature

(A) ${\mathrm{VO}}^{2+}$: Here the oxidation state of vanadium is $+4$.

The steps include:

$$\begin{gathered} \mathrm{x}-2=2 \\ \mathrm{x}=+4 \end{gathered}$$

• Therefore the oxidation state of vanadium in ${\mathrm{VO}}^{2+}$ is $+4$

The explanation for the incorrect option:

(B) $\mathrm{V}{\left(\mathrm{OH}\right)}^{4+}$: Here the oxidation state of vanadium is $+5$.

The steps include:

$$\begin{gathered} \mathrm{x}-1=+4 \\ \mathrm{x}=4+1=+5 \end{gathered}$$

(C) ${{\mathrm{VO}}_2}^{+1}$: Here the oxidation state of vanadium is $+5$.

The steps include:

$$\begin{gathered} \mathrm{x}-4=+1 \\ \mathrm{x}=+5 \end{gathered}$$

(D) ${\left[{\mathrm{VO}}_3\mathrm{OH}\right]}^{2-}$: The oxidation state of vanadium is $+5$.

The steps include:

$$\begin{gathered} \mathrm{x}-6-1=-2 \\ \mathrm{x}=+5 \end{gathered}$$

Therefore, option(A) is correct. i.e., ions in which vanadium is present in a $+5$ oxidation state except is ${\mathrm{VO}}^{2+}$.