Question

Calculate the oxidation number :
(i) Mo in (NH₄)₂MoO₄
(ii) Ni in [Ni(CN)₄]^2-

Answer 1

(i) Suppose oxidation number of Mo in (NH₄)₂MoO₄ = x
2 (+1) + x+ 4 (-2) = 0
2 + x – 8 = 0
x – 6 = 0
x = + 6

(ii) Suppose, oxidation number of Ni in [Ni(CN)₄]^2- = + x
x + 4 (-1) = -2
x – 4 = -2
x = -2 + 4 = +2
∴ Oxidation number of Ni in [Ni(CN)₄ ]² = + 2