Question

Oxidation number of $Fe$ in $\left[Fe\right(SCN){]}^{+2}$ and $\left[Fe\right(H_{2}O{)}_6{]}^{+3}$ would be respectively-

• A. +3 and +3
• B. +3 and -3
• C. +2 and +2
• D. +2 and -2

Answer 1

The correct option is A +3 and +3

Let O.N. of $Fe$ is $x$ in $\left[Fe\right(SCN){]}^{2+}$ :
charge on $SCN=-1$
$\Rightarrow x-1=+2$
$\Rightarrow x=+3$

Let O.N. of $Fe$ is $y$ in $\left[Fe\right(H_{2}O{)}_6{]}^{3+}$ :
charge on $H_{2}O=0$
$\Rightarrow y+0=+3$
$\Rightarrow y=+3.$

Thus, option (a) is correct.