Question

# The ionic charges on chromate ion and dichromate ion respectively are:(a)-2, -2(b)-3, -2(c)-2, -4(d)-4, -2

-Chromate ion or chromate anion is present in chromate salts. When chromate salt dissociates, we get chromate ions. It consists of one chromium and four oxygen atoms. It is written as $CrO_{4}^{2-}$. The charge on the chromate ion is -2. The oxidation state of chromium in chromate ion is +6 and the oxidation state of oxygen is -2. There are four oxygen atoms, so we have to multiply -2 with four to get -8. By adding the oxidation state of chromium and total oxidation state of oxygen, we get -2. So, the ionic charge on chromate ions is -2.