Question

Relationship between the Titration Curve and the Acid-Base Properties of Glycine A 100 ml solution of 0.1 m glycine at pH 1.72 was titrated with 2 m NaOH solution The pH was monitored and the results were plotted as shown in the graph. The key points in the titration are designated Ito V. For each of the statements (a) to (o), identify the appropri- ate key point in the titration and justify your choice: Glycine is present predominantly as the species *H,N-CH-COOH

Answer 1

The titration curve of glycine with NaOH provides information about its acid-base properties. Point V on the curve corresponds to the formation of a salt, where glycine is predominantly in its neutral form. This indicates the appropriate key point in the titration.

Step-by-step explanation:

The titration curve of glycine with NaOH can provide information about its acid-base properties. The graph shows the pH change as NaOH is added to the 0.1 M glycine solution at pH 1.72. To identify the appropriate key points, we need to consider the behavior of glycine during titration.

Glycine, with the formula H₂N-CH₂-COOH, can act as both an acid and a base due to the presence of amino and carboxyl groups. As NaOH, the strong base, is added, it will react with the acidic carboxyl group (-COOH) of glycine to form a salt, making the solution less acidic and increasing the pH. Therefore, the key point corresponding to the formation of the salt is point V on the titration curve. This is where glycine is predominantly in its neutral form, H₂N-CH₂-COO⁻.