ชุดทดลองการสมดุลการแยกตัวด้วย Cobra SMARTsense

rinciple

Carboxylic acids are potential electrolytes which exist in a weakly dissociated condition in aqueous solutions. The location of the dissociation equilibrium is quantitatively described by the Ka or pKa value which can be determined with potentiometric measurements.

Benefits

• Simplified implementation: all pre-settings already prepared
• Drop counter optimizes the experimental procedure

Tasks

1. Measure the alteration of the pH value during a titration of approximately 0.1 molar aqueous solutions of formic acid, acetic acid, monochloroacetic acid, propionic acid, butyric acid and lactic acid with a 0.1 molar sodium hydroxide solution at constant temperature using Cobra SMARTsense-system.
2. From the neutralisation curves read the pKa values of the acids and compare them.

Learning objectives

1. True and potential electrolytes
2. Strong and weak acids
3. Law of mass action
4. Henderson-Hasselbalch equation
5. Dissociation constant and pKa value
6. Substituent effects
7. Potentiometry