Question

Analysis show that nickel oxide consists of nickel ion with 96% ions having s configuration and 4% having d configuration. Which amongst the following best represents the formula of the oxide?

• A. $N{i}_{1.02}{O}_{1.00}$
• B. $N{i}_{0.96}{O}_{1.00}$
• C. $N{i}_{0.98}{O}_{0.98}$
• D. $N{i}_{0.98}{O}_{1.00}$

Answer 1

The correct option is D $N{i}_{0.98}{O}_{1.00}$

$Ni=3d^{8}4s^2\text{(At.no.=28)}$

$\therefore N{i}^{2+}=3d^8$ and $N{i}^{3+}=3d^7$

Hence, ${96}^{\wedge }$ ion of $N{i}^{2+}$ and $4\%$ ions of $N{i}^{3+}$ are present, Let number of $O^{2-}$ ion present in the crystal $=x$.

Applying electroneutrality rule, Total positive charge $=$ Total negative charge

$96\times 2$ (+ve charge) $+4\times 3($ +ve charge $)=x\times 2$ (-ve charge) $\therefore 96\times 2+4\times 3-2x=0\Rightarrow x=1.02$

So formula of crystal $N{i}_{1.00}{O}_{1.02}$ or $N{i}_{1.00}$ or $N{i}_{0.98}{O}_{1.00}$