CrO3 reacts with HCl to form chromyl chloride gas. — d and f Block Elements Chemistry Question

💡 Solution & Explanation

Step 1: Heavy metal nitrates like zinc nitrate, Zn(NO3)2, decompose upon heating to yield the metal oxide, nitrogen dioxide, and oxygen. Step 2: The chemical equation for the decomposition is: 2Zn(NO3)2 --Δ--> 2ZnO + 4NO2 + O2. Step 3: Therefore, the solid residue left after thermal decomposition is zinc oxide (ZnO), which corresponds to option (b).