Question

What is the ratio of Fe+3 ions to O2- ions in a neutral compound?

a.1:2
b.2:1
c.2:3
d. 3:2

Answer 1

In a neutral compound, the charges must balance, the net charge should be zero.

Since the charge of Fe is 3+ and that of O is 2-, therefore, there should be 2 Fe 3+ ions per 3 O2- ions in order to have a net charge of zero. 

Answer 2

it's a ratio of 2:3, so C