Liquid vegetable oils are converted to solid margarine by the use of

Liquid vegetable oils are converted to solid margarine by the use of

hydrogen gas
chlorine gas
carbon dioxide gas
oxygen gas
This question was previously asked in
UPSC NDA-2 – 2022
The correct answer is hydrogen gas.
Liquid vegetable oils are typically unsaturated fats, meaning they contain carbon-carbon double bonds. To convert these liquid oils into solid or semi-solid fats like margarine, hydrogen gas is added across the double bonds in the presence of a catalyst (usually nickel, palladium, or platinum). This process is called hydrogenation.
Partial hydrogenation can lead to the formation of trans fats, which have been linked to negative health effects. Modern hydrogenation processes aim to minimize trans fat formation while achieving the desired consistency.