Bleaching powder (CaOCl₂) releases chlorine when treated with: MCQ with Answer and Explanation

Explanation:
Ostwald process: NH₃ oxidized to NO over Pt-Rh catalyst at 800°C. Fe for Haber; Ni for hydrogenation; V₂O₅ for SO₂ oxidation.

Explanation:
Boyle's law states that at constant temperature, the volume of a given mass of gas is inversely proportional to pressure: PV = constant. So P ∝ 1/V. Charles' law relates V and T at constant P. Gay-Lussac's law relates P and T at constant V. Boyle's law is used in syringes and scuba diving. Graph of P vs V is a hyperbola; P vs 1/V is a straight line.

Explanation:
Atomic number 20 is calcium (Ca). Electron shells fill according to 2n²: K=2, L=8, M can hold 18 but fourth shell (N) starts after 8 electrons in M due to energy level considerations (Aufbau principle). So Ca configuration is 2,8,8,2. It has 2 valence electrons, belongs to Group 2, Period 4. Its nearest noble gas is Ar (2,8,8).