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JEE Advanced levelSingle correct optionDifficulty 3 of 3el138

The antioxidant action of BHT (2,6-di-tert-butyl-4-methylphenol) is best explained by the fact that

  1. Aits carboxylic acid group lowers the pH of the fat and stops oxidation
  2. Bits tert-butyl groups are oxidised first, leaving the fat untouched
  3. Cits methyl group reacts with oxygen to give a stable peroxide that kills microbes
  4. Dits phenolic O-H donates a hydrogen atom to chain-carrying radicals, giving a resonance-stabilised and sterically shielded phenoxyl radical

Answer: D

BHT has an O-H group that readily gives up an H atom to peroxy radicals, terminating the autoxidation chain. The resulting radical is delocalised into the ring and shielded by the two ortho tert-butyl groups, so it does not propagate the chain. BHT has no carboxylic acid group and does not act by killing microbes.
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