Which of the following hydrocarbons generally produces a clean flame?

Ethane is the hydrocarbon that generally produces a clean flame. As an alkane, ethane is a saturated hydrocarbon, meaning it contains only single bonds and has a high hydrogen-to-carbon ratio. Saturated hydrocarbons typically undergo complete combustion in the presence of sufficient oxygen, resulting in a blue, non-sooty flame. In contrast, unsaturated hydrocarbons like ethene and ethyne have a higher percentage of carbon, which often leads to incomplete combustion and a yellow, sooty flame.