Question

the diagram below shows part of a molecule that is found in proteins. when placed in water, the molecule ionizes to form the structure on the right: which statements correctly describe this molecule? select all that apply. the structure on the left is an acid. the structure on the left accepts a proton (h+) when placed in water. the structure on the left releases a proton (h+) when placed in water. the structure on the left is a base.

Explanation:

• According to the Brønsted - Lowry theory, an acid is a substance that donates a proton (\(H^{+}\)). The left - hand structure has a \(-COOH\) (carboxylic acid) group. In water, the \(-COOH\) group can ionize as \(R - COOH

ightleftharpoons R - COO^{-}+H^{+}\). So the left - hand structure is an acid and releases a proton (\(H^{+}\)) in water.

• A base is a proton acceptor. Since the left - hand structure donates a proton, it is not a base and does not accept a proton.

Answer:

• The structure on the left is an acid.
• The structure on the left releases a proton (\(H^{+}\)) when placed in water.