Analysis shows that nickel oxide has the formula `Ni^(0.98) 0 ,1.00` , what fractions of nickel exist as `Ni^(2+) and Ni^(3+)` ions ?

Explanation

In pure nickel oxide (NiO) the ratio of Ni and O atoms = `1 : 1`
Let x be the no. of Ni (II) atoms replaced by Ni (III) atoms in the oxide
`therefore` Number of Ni (II) atoms present = `0.98 - x`
Total charge on Ni atoms = charge on oxygen atom (`because` the oxide is neutral)
`2(0.98 - x) + 3x = 2`
`1.96 - 2x + 3x = 2`
`x = 2 - 1.96 = 0.04`
% of Ni (III) atoms in Nickel oxide = `("No. of Ni (iii) atoms")/("Total No. of Ni atoms") xx 100`
`= (0.04)/(0.98) = 4.01`%
% of Ni (II) atoms in nickel oxide = `100 - 4.01 = 95.99 %`