Question

How can one account for the fact that the carbon-oxygen single bond of acetic acid is shorter than the carbon-oxygen bond of ethanol? A) The carbon in the alcohol is sp2 hybridized and has a higher percent s-character that lengthens the C-O bond in the alcohol. B) The carbon in the carboxylic acid is sp3 hybridized and has a lower percent s-character that shortens the C-O bond in the carboxylic acid. C) The carbon in the carboxylic acid is sp hybridized and has a higher percent s-character that shortens the C-O bond in the carboxylic acid. D) The carbon in the carboxylic acid is sp2 hybridized and has a higher percent s-character that shortens the C-O bond in the carboxylic acid. E) The carbonyl oxygen withdraws electron cloud density which tends to pull the C-O single bond of a carboxylic acid closer to it.

Answer 1

D) The carbon in the carboxylic acid is sp2 hybridized and has a higher percent s-character that shortens the C-O bond in the carboxylic acid.

Step-by-step explanation:

The central carbon atom in acetic acid posses sp2 hybridization and the central carbon atom in ethanol posses sp3 hybridization. As the percent s-character in sp2 hybridized carbon atom is 33% whereas in sp3 hybridized carbon atom ther percent s-character is 25%. Higher is the s-character higher is the electronegativity and stronger is the tendency to pull shared pair of electron towards itself and thus, making the bond shorten and stronger. Thus, the carbon-oxygen single bond in acetic acid becomes short due to sp2 hybridization.

Therefore, option (D) is correct that the carbon in the carboxylic acid is sp2 hybridized and has a higher percent s-character that shortens the C-O bond.

See attachment for the chemical formula