Which catalyst is used in the hydrogenation of unsaturated vegetable oils? MCQ with Answer and Explanation

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.

Explanation:
Zymase, a complex of enzymes from yeast, catalyzes fermentation: C₆H₁₂O₆ → 2C₂H₅OH + 2CO₂. Invertase hydrolyzes sucrose; urease hydrolyzes urea; maltase converts maltose to glucose.

Explanation:
Half-life (T₁/₂) is the characteristic time for radioactive decay. For first-order kinetics, it is constant.