Vinegar is made of acetic acid(10%-25%) and water(nearly 80%). There are small number of other chemicals in it, in very minute quantities.
Acetic acids chemical formula is CH3COOH, therefore, it is generally considered as being the chemical formula for vinegar too.
The difference in percentage of acetic acid and water is what makes the vinegar strong or diluted. If more of acetic acid is present then, the vinegar is bound to strong and if water is present in bigger quantities(though it happens rarely, otherwise people won’t buy a weak sort of vinegar from the market) the vinegar is definitely going to be of less strength.
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