Question

The analysis shows that nickel oxide has the formula ${Ni}_{0.98}O$. What fraction of the nickel exists as ${Ni}^{3+}$ ions?

• A. $1$%
• B. $2$%
• C. $4$%
• D. $8$%

Answer 1

The correct option is C $4$%

${Ni}_{98}{O}_{100}$ means total charge due to oxygen atomes $=-2\times 100=-200$

$\therefore$ Total due to $Ni$ ions must be $+200$.

Let number of ${Ni}^{2+}ions=x$.

$\therefore$ Number of ${Ni}^{3+}ions=(98-x)$

$\therefore (+2)\left(x\right)+(+3)(98-x)=+200$

$x=94$

$\therefore$ Fraction of $Ni$ as ${Ni}^{2+}=\frac{94}{98}\times 100=96\%$

and fraction of $Ni$ as ${Ni}^{3+}=\frac{4}{98}\times 100=4\%$.

Hence, the correct option is $\text{C}$