KCET 2020 Chemistry Solved Paper

Let, the number of M2+ ions =x
Then, the number of M3+ ions will be 0.96−x
We know, the overall charge in the metal oxide is zero.
So, x(2)+(0.96−x)(3)+1(−2)=0
⇒2x+2.88−3x=2
⇒−x=−0.88
⇒x=0.88
∴ Number of M3+ ions =0.96−0.88=0.08
∴ Percentage of M3+ ions =

0.08

0.96

×100=8.33%