What is the chemical formula of vinegar?

The correct answer is option 2. CH₃COOH.

The chemical formula of vinegar is \(CH_3COOH\). This is the formula for acetic acid, which is the main component of vinegar. The other options you provided are:

\(HCOOH\): This is the formula for formic acid, which is a different organic acid.

\((COOH)_2\): This is the formula for oxalic acid, another organic acid.

\(C_6H_5COOH\): This is the formula for benzoic acid, yet another organic acid.

So, while all of these are organic acids, only \(CH_3COOH\) is the correct formula for vinegar.