Question
Chemistry Question on Organic Chemistry
The correct sequence of acidic strength of the following aliphatic acids in their decreasing order is: CH3CH2COOH, CH3COOH, CH3CH2CH2COOH, HCOOH
HCOOH>CH3COOH>CH3CH2COOH>CH3CH2CH2COOH
HCOOH>CH3CH2CH2COOH>CH3CH2COOH>CH3COOH
CH3CH2CH2COOH>CH3CH2COOH>CH3COOH>HCOOH
CH3COOH>CH3CH2COOH>CH3CH2CH2COOH>HCOOH
HCOOH>CH3COOH>CH3CH2COOH>CH3CH2CH2COOH
Solution
The acidic strength of carboxylic acids is influenced by the electron-withdrawing or electron-donating effects of alkyl groups:
HCOOH (formic acid) is the most acidic as it has no electron-donating alkyl group, which would reduce acidity.
CH3COOH (acetic acid) is less acidic because the methyl group (CH3) is weakly electron-donating.
CH3CH2COOH (propionic acid) is even less acidic due to the larger electron-donating ethyl group.
CH3CH2CH2COOH (butyric acid) is the least acidic because the longer alkyl chain has a stronger electron-donating effect.
The correct order of acidic strength is:
HCOOH > CH3COOH > CH3CH2COOH > CH3CH2CH2COOH.