Question

Analysis shows that nickel oxide has the formula Ni0.98O. What fractions of the nickel exist as Ni2+ and Ni3+?

Answer 1

98 Ni atoms are associated with 100 O atoms.

Out of 98 Ni atoms, suppose Ni present as Ni2+ = x

Then Ni present as Ni3+ = 98 – x

Total charge on x Ni2+ and (98 – x) Ni3+ should be equal to total charge on 100 O2– ions.

Hence, 2 × x + 3 × (98 – x) = 100 × 2 or 2x + 294 – 3x = 200

So, x = 94

Fraction of Ni present as Ni2+ = 94 / 98 x 100 = 96