Question

EAN of cobalt is 36 in knowing that atomic number of Co is 27, is present as

• A. Peroxide ion
• B. Dioxide ion
• C. Superoxide ion
• D. Oxide ion

Answer 1

The correct option is A Peroxide ion

Peroxide $=L_2^{2-}$, Dioxide $=2O^{2-}$
Superoxide $=O_2^{-}$, Oxide $=O^{2-}$
Ean $=Z-0.N+2\times C.N$
$\therefore$ If $O_2$ is present as $=O_2^{2-}$, then O.N. of Co is +3
$\therefore$ EAN $=27-3+2\times 6=36$