The acid used in car batteries is: MCQ with Answer and Explanation

Explanation:
Calcination involves heating an ore in limited supply or absence of air, often to convert carbonates/hydroxides to oxides and remove moisture or volatile impurities. Example: CaCO₃ → CaO + CO₂; Al(OH)₃ → Al₂O₃ + 3H₂O. Roasting is heating in excess air, usually for sulfide ores. Smelting uses reducing agents to obtain metal. Leaching uses chemicals.

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:
Two or more substances combine to form a single product: N₂ + 3H₂ → 2NH₃. This is a combination (synthesis) reaction. Decomposition involves a single compound breaking down. Displacement: one element displaces another. Double displacement: exchange of ions. The Haber process for ammonia is also a redox and reversible reaction. Combination can be exothermic.