As a go through my study guide, I'm finding that I'm getting esters and normal stoic acids confused. How can you tell when a stoic acid is an ester and when its not? Or are they always the same thing? Thanks for explaining this.

Would you explain what a stoic acid is. I don't know. Then I can answer your question.

A stoic acid is when you have an oxygen with a double bond directly underneath leading to a C which is connected by a single bond to an O.

I must admit that I have never heard of a stoic acid before. Thanks for the explanation.

An ester is RCOOR' whereas an acid is
RCOOH.
What is attached to the RCOO- is the secret. If you attach a H atom, it is an acid. If you attach another R group (CH3 or higher), it is an ester.

To differentiate between esters and carboxylic acids, it's important to understand their structures and chemical properties.

Esters: Esters are organic compounds formed by the reaction between an alcohol and a carboxylic acid. They have the general formula RCOOR', where R and R' represent alkyl or aryl groups. Esters are characterized by a carbonyl group (C=O) and an oxygen atom bonded to a carbon atom.

Carboxylic Acids: Carboxylic acids are organic compounds characterized by the carboxyl group (-COOH). They have the general formula RCOOH, where R represents an alkyl or aryl group. Carboxylic acids are characterized by a carbonyl group (C=O) and a hydroxyl group (OH) bonded to the same carbon atom.

Now, to distinguish between esters and carboxylic acids:

1. Functional Groups: Esters have a carbonyl group (C=O) and an oxygen atom bonded to a carbon atom. Carboxylic acids have a carbonyl group (C=O) and a hydroxyl group (OH) bonded to the same carbon atom.

2. Naming: Esters are named by combining the alkyl or aryl group from the alcohol part with the alkyl or aryl group from the carboxylic acid part, along with the suffix "-ate" (e.g., methyl acetate). Carboxylic acids are named by replacing the "-e" ending of the corresponding alkane with "-oic acid" (e.g., ethanoic acid).

3. Odor: Esters often have pleasant, fruity, or sweet odors and are commonly used as flavorings and fragrances. Carboxylic acids typically have sharp, pungent, or sour odors.

4. Reactivity: Carboxylic acids are acidic compounds that can donate a proton (H+) to a base. Esters do not readily donate protons and are relatively unreactive under neutral conditions. They require specific conditions, such as the presence of a strong acid or base, to react.

Remember, esters and carboxylic acids are not the same thing. They have different functional groups, naming conventions, smells, and reactivity. By analyzing these characteristics, you can distinguish between the two and avoid confusion.