The foul smell of rancid butter is due to-

Correct option is A

The correct answer is (a) Butyric acid.
· The foul smell of rancid butter is primarily due to the formation of butyric acid.
· When butter goes rancid, the fats (triglycerides) break down, and butyric acid is released, which has a very strong and unpleasant odor.
Other options explained:
· Palmitic acid: This is a saturated fatty acid found in fats and oils, but it does not contribute to the rancid smell.
· Stearic acid: Another saturated fatty acid, commonly found in animal fats, but it does not cause the unpleasant smell of rancid butter.
· Caproic acid: Although it has a distinct smell, it is not the primary cause of the foul odor in rancid butter.