PVC's rigidity in its unplasticized form is due to: MCQ with Answer and Explanation

Explanation:
Electrolysis of water decomposes it into hydrogen and oxygen, not purification. Boiling kills microbes, filtration removes particulate matter, chlorination disinfects. Other methods: UV treatment, ozonation, reverse osmosis, distillation. Electrolysis is a chemical decomposition technique.

Explanation:
Catenation is the ability of carbon atoms to form long chains, rings, and networks via covalent bonds. This leads to a vast number of organic compounds. Silicon also catenates but to lesser extent.

Explanation:
Nickel (finely divided) is used as a catalyst in the hydrogenation of unsaturated vegetable oils to saturated fats (vanaspati ghee). The reaction adds H₂ across double bonds. Platinum and palladium are also hydrogenation catalysts but nickel is cheaper and industrially preferred. Fe is used in Haber process for ammonia synthesis, V₂O₅ in contact process for H₂SO₄. Catalysts provide an alternative pathway with lower activation energy.