Half-life of a radioactive substance is 5 years. After 10 years, how much of the original amount remains? MCQ with Answer and Explanation

Explanation:
Highly reactive metals like sodium, potassium, calcium, and aluminum cannot be reduced by chemical reducing agents like carbon. They are extracted by the electrolysis of their molten chlorides or oxides. For example, sodium is extracted by the electrolysis of molten NaCl in the Down's cell.

Explanation:
In this reaction, chlorine (oxidation state 0) reacts with hot, concentrated NaOH. It forms NaCl where Cl is -1 (reduction) and NaClO3 where Cl is +5 (oxidation). Since the same element, chlorine, is both oxidized and reduced, it undergoes a disproportionation reaction.

Explanation:
Polythene (polyethylene) softens on heating and can be remolded, thus thermoplastic. Bakelite and melamine are thermosetting (cannot be remolded). Vulcanized rubber is also thermoset due to cross-linking. Thermoplastics have linear or branched chains, no cross-links.