The acidity of carboxylic acids is determined by the stability of the carboxylate ion formed when the acid donates a proton (\(H^+\)). Generally, electron-withdrawing groups enhance the stability of the carboxylate ion, leading to stronger acids.
Now, let's analyze each carboxylic acid in the given list:
A. \(CH_3COOH\): Acetic acid is a simple carboxylic acid with a methyl group. It is a relatively weak acid.
B. \(CH_3CH_2COOH\): Propanoic acid has an ethyl group, which is larger than the methyl group in acetic acid. The increased size of the alkyl group tends to decrease the acidity.
C. \(C_6H_5CH_2COOH\): Benzylacetic acid has a benzyl group attached. The benzyl group is electron-donating and destabilizes the carboxylate ion, making it a weaker acid compared to the previous two.
D. \(C_6H_5COOH\): Benzoic acid has a phenyl group, which is less donating than the benzyl group. The phenyl group is somewhat electron-withdrawing due to the aromatic ring. This electron-withdrawing effect enhances the stability of the carboxylate ion, making benzoic acid stronger than the other acids in the list.
So, the correct order of increasing acid strength is \(D > C > A > B\), which corresponds to option 3: \(D > C > A > B\). I appreciate your patience and hope this explanation clarifies the reasoning behind the answer. |
