Question

The oxidation number of cobalt in $K_3[Co{(N{O}_2)}_6]$ is:

• A. 6
• B. -3
• C. 3
• D. -6

Answer 1

Answer: (C)

$K_3[Co{(N{O}_2)}_6]\to$ or $3K^{+}+{[Co{(N{O}_2)}_6]}^{3-}$ Now, ${[Co{(N{O}_2)}_6]}^{3-}$ $\because$ In ${\text{NO}}_2^{-},$ oxidation state of ${\text{NO}}_2^{-}=-1$ $x+(-1\times 6)=-3$ $x-6=-3$ $x=+6-3=+3$