Question

Draw structures for all the saturated carboxylic acids with four carbon atoms per molecule.

Short answer

Answer: The two saturated carboxylic acids with four carbon atoms per molecule are butanoic acid and 2-methylpropanoic acid. Butanoic acid has a straight chain structure: H H H H | | | | H-C-C-C-C-O-H | O || O 2-methylpropanoic acid has a branched structure: H H H | | | H H-C-C-C-O-H | | | H H O || O

Step-by-step solution

Identify the General Structure of Four Carbon Saturated Carboxylic Acids

In order to draw the structures of the saturated carboxylic acids with four carbon atoms per molecule, we begin with their general structure: C_4H_9COOH. Saturated compounds only contain single bonds, which means we will only consider single bonds between the carbon and hydrogen atoms.

Draw the Straight Chain Structure

The simplest structure for the four-carbon-carboxylic acid is the straight chain, where all carbon atoms are connected in a row. The structure for this isomer, named butanoic acid, can be drawn as: H H H H | | | | H-C-C-C-C-O-H | O || O

Draw Branched Structures

If we consider branched structures, there are only a few possible isomers. One option is to create a three-carbon-based chain with a methyl (CH3) group branching off on the middle carbon. This isomer is named 2-methylpropanoic acid, and the structure can be written as: H H H | | | H H-C-C-C-O-H | | | H H O || O There are no other branching possibilities for saturated carboxylic acids with four carbon atoms since placing the carboxyl group closer to the middle would result in the butanoic acid structure, while an ethyl group at the middle of a two-carbon chain would also result in butanoic acid. So, the two saturated carboxylic acids with four carbon atoms per molecule are butanoic acid and 2-methylpropanoic acid.