John Dalton is known for: MCQ with Answer and Explanation

Explanation:
C₄H₁₀ (butane) follows CnH₂n+2, indicating no double or triple bonds, i.e., saturated alkane. C₂H₄ is ethene (alkene), C₃H₆ could be propene or cycloalkane (but alkene formula), C₂H₂ is ethyne (alkyne). Saturated hydrocarbons contain only single bonds and undergo substitution reactions.

Explanation:
Synthetic detergents are primarily sodium salts of long-chain alkyl benzene sulphonic acids or alkyl hydrogen sulphates. Unlike soaps (which are carboxylate salts), detergents do not form insoluble precipitates with calcium and magnesium ions in hard water, making them effective cleansers.

Explanation:
Aluminium goes from 0 to +3 oxidation state (Al → Al³⁺ + 3e⁻), so it is oxidized. Iron goes from +3 to 0 (Fe³⁺ + 3e⁻ → Fe), reduced. This is a thermite reaction, highly exothermic, used for welding. Al is the reducing agent, Fe₂O₃ is the oxidizing agent. Oxidation is loss of electrons.