acidic nature of compounds depends upon how compound releases H+ in the solution for any organic compound as the -I effect or -R effect of compound increases acidic nature also increases for example ClCH2COOH is more acidic than CH3COOH because in CH3COOH there is +Ieffect of alkyl group whcich decreases acidic nature.always remember hydrogen bonding decreases acidic nature for ex.HCl is more acidic than HF and RSH is more than ROH.