Question

what will be the odour of onion in acid

Answer 1

onion itself contains acid. and I think it is oxidic acid

Answer 2

Onion has a characteristic smell.When a basic solution like sodium hydroxide solution is added to a cloth strip treated with onion extract then the onion smell cannot be detected.An acidic solution like hydrochloric acid does not destroy thesmell of onions.This can be used as a test for acids and bases.