For example 2,3 Dimethylpentane has substituent groups off of it's second and third carbon atoms. If a person studies the names of compounds it is not hard at all to figure out the composition of them. They are named the same way that alkanes are named in that the name of the compound also tells a person what is in the compound. Alcohols are characterized by having a hydroxide molecule attached to the carbon chain. Carboxylic acids are made by the oxidation of primary alcohols and aldehydes.
Citric acid is found in juices or citrus fruits and is responsible for their tart flavor.