What is the oxidation number of carbon in $\mathrm{K}_2 \mathrm{C}_2 \mathrm{O}_4$ ?
What is the oxidation number of carbon in $\mathrm{K}_2 \mathrm{C}_2 \mathrm{O}_4$ ?
-2
-3
+3
+4
Solution
Let oxidation state of C be $x$ in $\mathrm{K}_2 \mathrm{C}_2 \mathrm{O}_4$.
$\begin{array}{ll}
& 2(+1)+2 x+4(-2)=0 \\
& 2+2 x-8=0 \\
& 2 x=6 \\
\therefore \quad & x=+3
\end{array}$