Which gas is primarily responsible for the greenhouse effect from burning fossil fuels? MCQ with Answer and Explanation

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.

Explanation:
Methyl orange is red in acidic (pH4.4). So yellow indicates pH above 4.4; could be neutral or basic.

Explanation:
Petroleum originates from microscopic marine organisms (plankton) that sank to the seabed and were transformed by heat/pressure over millions of years. Coal is from land plants.