Acetic acid , also known as ethanoic acid, has a molecular formula CH3COOH. It is a weak monoprotic acid which is able to lose a proton from its acid functional group (-COOH) readily and produce a conjugate base, acetate anion. Acetic acid is also a polar protic solvent as it dissolves readily and is miscible in other polar solvents such as water. However, its polar nature makes it insoluble and immiscible in non-polar solvents such as octane. Using acetic acid as a starting reagent, it readily forms other organic reagents such as acetyl chloride and ethanol though substitution and reduction reactions respectively. Acetic acid can also corrode metals such as iron, magnesium and zinc, forming hydrogen gas and metal acetates. But since aluminum forms a protective layer of aluminum oxide on its surface, it is acid-resistance and hence aluminum tanks are used as an option to transport acetic acid. Alternatively, high-density polyethylene (HDPE) drums can also be used to transport acetic acids as due to their resistivity.