Question

Analysis shows that nickel oxide has the formula $N{i}_{0.98}O$. The percentage of $Ni$ present as $N{i}^{2+}$ and $N{i}^{3+}$ respectively will be

• A. 99%, 1%
• B. 98%, 2%
• C. 97%, 3%
• D. 96%, 4%

Answer 1

Answer: (D)

If the amount of $O$-atoms $=100$
then, the amount of $Ni$-atoms $=98$
Let $N{i}^{2+}=x$, then $N{i}^{3+}=98-x$
Total charge on $100,O^{-2}$ ions $=200$
Total charge on $N{i}^{2+}$ and $N{i}^{3+}=2x+3(98-x)$
For neutrality, $2x+3(98-x)=200$ or, $x=94$.
$\%$ of $N_1^{2+}=\frac{94}{98}\times 100=96\%$
and $\%$ of $N{i}^{3+}=100-96=4\%$.