Question

The simplest amino acid is glycine, H₂NCH₂CO₂H. The common feature of amino acids is that they contain the functional groups: an amine group, –NH₂, and a carboxylic acid group, –CO₂H. An amino acid can function as either an acid or a base. For glycine, the acid strength of the carboxyl group is about the same as that of acetic acid, CH₃CO₂H, and the base strength of the amino group is slightly greater than that of ammonia, NH₃.

a) True
b) False

Answer 1

Glycine in 1 M HCl forms an NH₃⁺+ ion, while in 1 M KOH it forms a COO⁻ ion. In water, glycine exists as a zwitterion. Boric acid reacts with water to form a tetrahedral B(OH)₄⁻ anion with boron in sp³ hybridization.

Step-by-step explanation:

Glycine is the simplest amino acid with the chemical formula H₂NCH₂CO₂H, comprising an amine group and a carboxylic acid group. When dissolved in 1 M HCl, glycine will gain a proton on its amine group due to the strong acidity of HCl, resulting in a positively charged ammonium ion (NH₃⁺+). Conversely, in 1 M KOH, the carboxylic acid group will lose a proton to the strong base KOH, resulting in a negatively charged carboxylate ion (COO⁻).

When glycine is dissolved in water, it exists in a zwitterionic form, where the carboxyl group is ionized (COO⁻), and the amine group is protonated (NH₃⁺+), reflecting the relative acid and base strengths of these groups. The structure can be depicted with a Lewis structure showing the charges on the respective functional groups.