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

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. 

nacl is added to the aqueous of what? ? in order to get a proper answer you have to specify the exact composition of the aqueous solution.

your parents i think this could be it