Which general formula represents a carboxylic acid?

Which general formula represents a carboxylic acid?

• A. R-COOH
• B. R-CHO
• C. R-O-R
• D. R-OH

Answer: (A)

Carboxylic acids have a specific group called the carboxyl group, which is a carbon double-bonded to oxygen and single-bonded to a hydroxyl group (-COOH). The carbon of this group is attached to an R, which stands for any alkyl or aryl fragment. Together this gives the general formula R-COOH, capturing both the carbonyl and the acidic OH. That acidic hydrogen on the -OH can be donated, and the resulting negative charge is stabilized by resonance between the two oxygens, which explains the characteristic acidity of carboxylic acids. Other common functional groups have different patterns: aldehydes feature -CHO, ethers have -O- linking two R groups, and alcohols have -OH attached directly to an R. So the general representation that describes a carboxylic acid is R-COOH.

Carboxylic acids have a specific group called the carboxyl group, which is a carbon double-bonded to oxygen and single-bonded to a hydroxyl group (-COOH). The carbon of this group is attached to an R, which stands for any alkyl or aryl fragment. Together this gives the general formula R-COOH, capturing both the carbonyl and the acidic OH.

That acidic hydrogen on the -OH can be donated, and the resulting negative charge is stabilized by resonance between the two oxygens, which explains the characteristic acidity of carboxylic acids.

Other common functional groups have different patterns: aldehydes feature -CHO, ethers have -O- linking two R groups, and alcohols have -OH attached directly to an R. So the general representation that describes a carboxylic acid is R-COOH.