See image — AITS & Test Series Chemistry Question

💡 Solution & Explanation

           4 2 4 2 3 2 3 FeSO .7H O FeSO Fe O SO SO X Y A B C     4 2 2 4 5 FeSO H O NO Fe H O NO SO Y D       Number of unpaired electron in (D) are 3. Molar mass of compound (A) is 160. Molar mass of compound (B and C) is 144. x = 3, a = 160, b = 144.