Question

The oxidation state of Chromium $\left(Cr\right)$ in the complex $\left[Cr\right(H_{2}O{)}_{4}C{l}_2{]}^{+}$ is :

• A. $+5$
• B. $+3$
• C. $+7$
• D. $-5$

Answer 1

The correct option is B $+3$

The complex $\left[Cr\right(H_{2}O{)}_{4}C{l}_2{]}^{+}$ has a overall charge $+1$
Let $x$ be the oxidation state of $Cr$
Since $H_{2}O$ is a neutral molecule, it has $0$ overall charge.
Charge on $Cl=-1$
$x+(4\times 0)+(2\times (-1\left)\right)=+1x=+3$