Why Formic Acid is Stronger than Acetic Acid

Formic acid is stronger than acetic acid due to the partial positive charge on the carbon atom of the carboxylic acid group (-COOH) in formic acid.

The increase in positive charge on the carbon atom weakens the O-H bond in the carboxylic acid group, making it more prone to donating a proton (H+).

Formic acid has an electron-attracting hydrogen atom attached to the carbon, leading to an increase in the positive charge on the carbon atom of the carboxylic acid group.

On the other hand, acetic acid has a methyl group (-CH3) attached to the carbon of the carboxylic acid group, causing a decrease in the positive charge on the carbon atom. Because, methyl group (-CH3) is an electron donating group.