Concentrated aqueous solution of CuCl2 is green in colour. — d and f Block Elements Chemistry Question

💡 Solution & Explanation

Step 1: 'Philosopher's wool' is a historical alchemical name for a white zinc compound. Step 2: When zinc metal is burned in air, it produces a white, wool-like fluffy solid of zinc oxide. Step 3: Therefore, zinc oxide (ZnO) is known as philosopher's wool, which corresponds to option (a).