There are many authentic Hadiths concerning the punishment for one who drinks alcohol which say that his prayers will not be accepted for forty days. The fact that his prayers are not accepted does not mean that they are not valid, or that he should give up praying, rather it means that he will not be rewarded for them.

If the alcohol which this mouthwash contains is not intoxicating, then it is OK to use it, so long as it is not harmful, because what is prohibited is only that which is intoxicating.

Alcohol is haram because it is intoxicating and contains a substance that makes people lose their minds. Allah has forbidden everything that harms the body and mind. For more, see the detailed answer.

1- Vinegar is a well-known basic foodstuff, made from wine of which the composition has changed so that it is no longer sweet but is acidic or sour. 2- When wine turns to vinegar by itself, without any deliberate treatment needed for it to be changed, it is permissible to eat, drink and handle. 3- If the wine has become vinegar because of deliberate treatment, by adding vinegar, onions, salt etc., or by any other process, in this case the scholars differ as to whether it is permissible or not. For more, see the detailed answer.