According to Boyle's law, the product of pressure and volume for a fixed mass of gas at constant temperature is: MCQ with Answer and Explanation

Explanation:
Marble is primarily calcium carbonate (CaCO₃). It reacts with acid rain (containing H₂SO₄ and HNO₃) to form soluble salts, causing erosion: CaCO₃ + H₂SO₄ → CaSO₄ + H₂O + CO₂. This is why monuments like Taj Mahal are affected. CaCO₃ is basic, so it neutralizes acid. Restoration and pollution control are needed to protect heritage.

Explanation:
Hydrochloric acid (HCl) is commonly used for pickling (cleaning) steel to remove rust and scale (iron oxides) before further processing like galvanizing or plating. Reaction: Fe₂O₃ + 6HCl → 2FeCl₃ + 3H₂O. Sulfuric acid is also used. Nitric acid is an oxidizer and would passivate some metals. Acetic acid is too weak.

Explanation:
Chlorofluorocarbons (CFCs), used in refrigerants and aerosols, reach the stratosphere where UV radiation breaks them down, releasing chlorine atoms. These chlorine atoms catalytically destroy ozone (O₃) molecules, leading to the depletion of the ozone layer, particularly over Antarctica.