Titration of a polyvalent acid with a strong base with Cobra SMARTsense

Principle

Phosphoric acid and sodium hydroxide are to be used to give an example of a titration of a polyvalent acid with a strong base.

Benefits

• Drop counter optimizes the experimental procedure
• Simplified implementation: all pre-settings already prepared
• Extensive automation of the experiment allows concentration on the learning objectives

Tasks

1. Measure the alteration of the pH value during a titration of an aqueous solution of phosphoric acid with a 0.1 molar sodium hydroxide solution at constant temperature using the Cobra4 system.
2. From the titration curve read the equivalence points and pKa values.
3. Determine the concentration of the acid.

Learning objectives

• Phosphoric acid
• Sodium hydroxide
• Polyvalent acid
• pKa values
• Proteolysis
• pH value
  

Necessary accessories

• Precision balance 620g/0.001g