Is it wrong to use vinegar as child punishment?

Yes: Vinegar is a strong acid and can damage teeth if not diluted with other foods when cooking. If used as a punishment, it is a very negative consequence that is not a natural consequence. (natural consequence would be being cold when a child refused to wear or carry a coat in the cold.) most behavior experts support positive parenting. Talk with your pediatrician. Consider a psychologist if needed.

Yes: All things like that do is teach your child that it is ok to do mean things to people when you don't like their behavior. There will never be a positive long term outcome from this type of punishment. You will make your child afraid of you, and more likely to just hide their behaviors and mistakes rather to coming to you with them and learning from their mistakes. Vinegar is an acid - not pleasant.