Question

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

• A. $4\%$
• B. $96\%$
• C. $98\%$
• D. $2\%$

Answer 1

The correct option is B $96\%$

$\begin{array}{c}{\text{Given Nickel oxide Ni}}_{0.8}O\\ \text{oxidation number}\text{of Ni}=x\\ \begin{array}{c}0.98\times x-2\times 1=0\\ x=\frac{2}{0.98}\\ x=\frac{200}{98}=\frac{100}{49}\end{array}\end{array}$

$\begin{array}{c}\text{Let}x\text{ions be in}+2\text{oxidation state}\\ (98-x)\text{ions be}+3\text{oxidation state}\end{array}$

$N{i}^{+2}N{i}^{+3}$

$\begin{array}{c}2x+(98-x)3-2\times 100=0\\ x=94\end{array}$

$\begin{array}{c}\text{Fraction of}N{i}^{+2}\text{ions}=\frac{94}{98}=0.96\\ \text{Hence percentage of}N{i}^{+2}\text{ions}=96\%\end{array}$