Question 16

Analysis shows that nickel oxide has the formula Ni_0.98 O_1.00. What fractions of nickel exist as Ni²⁺and Ni³⁺ions?

Answer

The formula of nickel oxide is Ni_0.98 O_1.00.

Therefore, the ratio of the number of Ni atoms to the number of O atoms,

Ni : O = 0.98 : 1.00 = 98 : 100

Now, total charge on 100 O^{2 -} ions = 100 × ( - 2) = - 200

Let the number of Ni²⁺ions be x.

So, the number of Ni³⁺ions is 98 - x.

Now, total charge on Ni²⁺ions = x(+2) = +2x

And, total charge on Ni³⁺ions = (98 - x)(+3) = 294 - 3x

Since, the compound is neutral, we can write: 2x+ (294 - 3x) + ( - 200) = 0

⇒ - x+ 94 = 0 ⇒ x= 94

Therefore, number of Ni²⁺ions = 94

And, number of Ni³⁺ions = 98 - 94 = 4

Hence, fraction of nickel that exists as Ni²⁺ = 94/98 = 0.959

And, fraction of nickel that exists as Ni³⁺ = 4/98 = 0.041

Alternatively, fraction of nickel that exists as Ni³⁺= 1 - 0.959 = 0.041

5 Comment(s) on this Question

Akash Tyagi 2018-12-10 06:29:25

Really helppul

Manish 2018-09-02 21:17:34

Well explained

khyati 2018-04-12 21:08:36

I was asking about only ni2+

wonder 2018-03-17 10:20:21

I didn't really understand.How can it be 98-x for Ni3+ ions ???

Athar 2017-11-24 11:12:03

Thanks very nice explaInation

t/s	0	400	800	1200	1600	2000	2400	2800	3200
10² × [N₂O₅] mol L^-1	1.63	1.36	1.14	0.93	0.78	0.64	0.53	0.43	0.35