Question

why is acetic acid called weak acid though it has four hydrogen atoms in the molecules

Answer 1

acetic acid is CH3COOH
we have to see the no. of atoms in the carboxylic acid functional group.CH3 is a homologous series.
so, COOH. this doesn't ionize completely in water . so it is a weak acid

hope this helps you

Answer 2

Acetic acid is called weak acid because,
1.it does not ionized completely.
2.it produce less no. Of H+ ions on mixing with water than other acids.
3.it's melting point is only 293K.
4.it forms ice like flakes during winter season.