Question

Analysis shows that an oxide ore of nickel has formula $Ni_{0.98} O_{1.00}$ The percentage of nickel as $Ni^{3+}$ ions is nearly

• A. 2
• B. 96
• C. 4
• D. 98

Answer 1

Answer: (C)

4

Answer 2

Let no. of nickel ions $= 98$ $\therefore$ No. of oxide ions $= 100$ Total negative charge on $O^{2-}$ ions $= 2 \times 100 = 200$ Let no. of $Ni^{3+}$ ions $= x$ $\therefore$ No. of $Ni^{2+}$ ions $= 98 - x$ $x \times 3 + (98 - x) \times 2 = 200$ $3x - 2x = 200 - 196$ $x = 4$ Percentage of nickel as $Ni^{3+} = \frac{4}{98} \times 100$ $= 4.08$