Question

The oxidation states of $\mathrm{Cr}\mathrm{in}\left[\mathrm{Cr}{\left({\mathrm{H}}_2\mathrm{O}\right)}_6\right]{\mathrm{Cl}}_3,\left[\mathrm{Cr}{\left({\mathrm{C}}_6{\mathrm{H}}_6\right)}_2\right]\mathrm{and}{\mathrm{K}}_2\left[\mathrm{Cr}{\left(\mathrm{CN}\right)}_2{\left(\mathrm{O}\right)}_2\right({\mathrm{O}}_2\left)\right({\mathrm{NH}}_3\left)\right]$ respectively are

• A. $+3,+2\mathrm{and}+4$
• B. $+3,0\mathrm{and}+6$
• C. $+3,0\mathrm{and}+4$
• D. $+3,+4\mathrm{and}+6$

Answer 1

The correct option is B

$+3,0\mathrm{and}+6$

The explanation for the correct option:

B: $+3,0\mathrm{and}+6$

Oxidation State:

• An atom's oxidation state (also known as its oxidation number) in a chemical compound gives information on how many electrons were lost from it and, as a result, describes the degree of oxidation of the atom.
• The imagined charge that an atom would carry if all of its links to other atoms were entirely ionic in nature can be used to determine an atom's oxidation state.

Oxidation state of $\mathrm{Cr}\mathrm{in}\left[\mathrm{Cr}{\left({\mathrm{H}}_2\mathrm{O}\right)}_6\right]{\mathrm{Cl}}_3$ is:

• $\begin{array}{rcl}\mathrm{x}+\left(0\times 6\right)-1\times 3& =& 0\\ \mathrm{x}& =& +3\end{array}$

Oxidation state of $\mathrm{Cr}\mathrm{in}\left[\mathrm{Cr}{\left({\mathrm{C}}_6{\mathrm{H}}_6\right)}_2\right]$ is:

• $\begin{array}{rcl}x+2\times 0& =& 0\\ x& =& 0\end{array}$

Oxidation state of $\mathrm{Cr}\mathrm{in}{\mathrm{K}}_2\left[\mathrm{Cr}{\left(\mathrm{CN}\right)}_2{\left(\mathrm{O}\right)}_2\right({\mathrm{O}}_2\left)\right({\mathrm{NH}}_3\left)\right]$ is:

• $\begin{array}{rcl}1\times 2+x-1\times 2-2-2\times 1& =& 0\\ x-6& =& 0\\ x& =& 6\end{array}$

Final Answer: Therefore, Option B is the correct option.