Which fuel has the highest calorific value per gram? MCQ with Answer and Explanation

Hydrogen has the highest calorific value (~150 kJ/g or 141.9 MJ/kg) because it has no heavier atoms like carbon and its combustion produces water, a very stable product. Methane ~55.5 kJ/g, coal ~25-35 kJ/g, wood ~17 kJ/g. Hydrogen is a clean fuel, but storage and production challenges remain. It can be used in fuel cells or internal combustion engines.