Chemical used for ripening of fruits

Fruit ripening is controlled by plant hormones. Among these, ethylene (C2H4) is known as the natural "ripening hormone": it is a simple gaseous hydrocarbon released by fruit tissue that triggers starch-to-sugar conversion, chlorophyll breakdown, and cell-wall softening — the changes that give a ripe fruit its colour, sweetness, and texture. Because it acts even in trace (parts-per-million) amounts, ethylene gas (or ethylene-releasing compounds such as ethephon) is used commercially to ripen fruits like bananas, mangoes, and tomatoes after harvest.

Among the given substances, ethylene is the one that performs this hormonal ripening role, so it is the chemical used for ripening of fruits.

• Methane is a simple hydrocarbon fuel gas; it has no established hormonal or physiological role in plant tissue, so it does not trigger ripening.

• Sulphuric acid is a strong corrosive acid used in industrial and laboratory reactions; it damages plant tissue rather than ripening it.

• Glucose is a simple sugar that is actually a product formed as starch breaks down during ripening, not the trigger that causes ripening.

Hence, Ethylene is the correct answer.