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

Explanation:
In diamond, each carbon atom is sp³ hybridized and forms four strong covalent bonds, utilizing all four valence electrons. No free electrons are available for conduction. Graphite has free delocalized electrons per carbon, making it a conductor.

Explanation:
2NaHCO₃ (heat) → Na₂CO₃ + CO₂ + H₂O. This is used in baking as CO₂ causes dough to rise. The sodium carbonate formed gives a bitter taste if excess soda is used, hence baking powder (with acid) is preferred.

Explanation:
Combustion of methane (CH₄ + 2O₂ → CO₂ + 2H₂O + heat) is an exothermic reaction, releasing heat to surroundings. Melting, evaporation, and sublimation are endothermic phase changes requiring heat absorption to overcome intermolecular forces. Exothermic reactions: burning, respiration, neutralization (usually), condensation, freezing. Endothermic: photosynthesis, cooking, melting, boiling.