Which catalyst is used in the decomposition of H₂O₂ in laboratory preparation of oxygen? MCQ with Answer and Explanation

Explanation:
At cathode (negative electrode), H⁺ ions are reduced: 2H⁺ + 2e⁻ → H₂(g). At anode (positive), water is oxidized: 2H₂O → O₂ + 4H⁺ + 4e⁻. Overall: 2H₂O → 2H₂ + O₂. The volume of H₂ collected is double that of O₂. Acidified water (with H₂SO₄) enhances conductivity. Platinum electrodes are used.

Explanation:
Boyle's law: P₁V₁ = P₂V₂. Given P₁=1.0 atm, V₁=2.0 L, P₂=4.0 atm. V₂ = (1.0 × 2.0) / 4.0 = 0.5 L. Volume decreases as pressure increases, because gas is compressible. The product PV is constant for a fixed mass of gas at constant T. Scuba divers experience this; as they dive deeper, pressure increases, reducing air volume in lungs.

Explanation:
Beta rays (β) consist of high-speed, high-energy electrons (β⁻) or positrons (β⁺) emitted from the nucleus during radioactive decay. In standard beta decay, a neutron converts into a proton and an electron, and the electron is ejected from the nucleus.