Question:
The oxidation states of iron atoms in compounds (A), (B) and $(\mathrm{C})$, respectively, are $x, y$ and $z$. The sum of $x, y$ and $z$ is _________.
Solution:
(6)
The oxidation states of iron in these compounds will be -
$\ln A, x+5(-1)+(-1)=-4 \Rightarrow x=+2$
In B, $y+4(-2)=-4 \Rightarrow y=+4$
In $\mathrm{C}, z=0$
The sum of oxidation states will be $=4+2+0=6$.