Question

Analysis shows that nickel oxide has the formula $N{i}_{0.98}{O}_{1.00}$. What fractions of nickel exist as $N{i}^{2+}$ and $N{i}^{3+}$ ions?

Answer 1

It is given that nickel oxide has the formula as $N{i}_{0.98}{O}_{1.00}$.

As per the formula, there are $98$ Ni ions for $100$ oxide ions.

Out of $98$ Ni ions, let $x$ ions be in $+2$ oxidation state.

$98-x$ ions will be in $+3$ oxidation state.

Oxide ion has $-2$ charge.

To maintain electrical neutrality, total positive charge on cations = total negative charge on anions.

$2x+3(98-x)+100(-2)=0x=94$

Fraction of $N{i}^{2+}$ ions $=\frac{94}{98}=0.96$

Fraction of $N{i}^{3+}$ ions $=\frac{98-94}{98}=0.04$

Hence, the fractions of nickel that exists as $N{i}^{2+}$ and $N{i}^{3+}$ are $0.96$ and $0.04$ respectively.