Question

Analysis shows that nickel oxide has the formula `Ni_(0.98)O_(1.00)`. What fractions of nickel "exist" as `Ni^(2+)` and `Ni^(3+)` ions?

Answer 1

Correct Answer - `Ni^(2+)=96%Ni^(3+)=4%`
The ratio of `Ni^(2+)` and `O^(2-)` ions in the pure sample of nickel oxide = `1:1`
Let x ions of `Ni^(2+)` be replaced by `Ni^(3+)` ions in the given sample.
Since the oxide is netural,
total charge on M atoms = Charge on oxygen atoms
`2(0.98-x)+3x=2`
`1.96-2x+3x=2`
`x=2-1.96=0.04`
`%` of `Ni^(3+)` ions in the oxide = `("No. of"Ni^(3+)"ions")/("Total no. of Ni atoms")xx100`
`=(0.04)/(0.98)xx100=4%`
`%` of `Ni^(2+)` ions in the oxide = `100-4=96%`