Question

1. functional groups are key groups of atoms in biological molecules. describe the carboxyl functional group that both acidic molecules in model 2 have in common.
2. recall the definition of an acid that you learned in chemistry. explain how the reaction below illustrates the acidic properties of lactic acid.

lactic acid
lactate ion

Explanation:

1. The carboxyl functional group (-COOH) is present in many biological molecules. It consists of a carbon - oxygen double - bond and a hydroxyl group attached to the same carbon atom. It can ionize, releasing a proton (H⁺), and is polar due to the electronegativity of oxygen atoms.
2. An acid is a substance that donates a proton (H⁺) in a solution. In the given reaction, lactic acid (C₃H₆O₃) donates a proton to water (H₂O), forming lactate ion (C₃H₅O₃⁻) and hydronium ion (H₃O⁺), which illustrates its acidic property as it acts as a proton - donor.

Answer:

1. The carboxyl functional group (-COOH) has a carbon - oxygen double - bond and a hydroxyl group on the same carbon, can ionize, and is polar.
2. An acid donates a proton. Lactic acid donates a proton to water to form lactate and hydronium ions, showing its acidic nature.