Hazards:
Hazards: HCl and NaOH are corrosive and toxic.
Chemicals and Solutions:
Sodium carbonate, 0.1 M (basic solution)
Sodium acetate, 0.1 M (basic solution)
Ferric nitrate, 0.1 M (acid solution)
Hydrochloric acid, 0.01 M (acidic solution)
Sodium hydroxide, 0.01 M (basic solution)
Materials:
pH meter
Combination pH electrode
Digital readout voltmeter and pH interface
Leads to connect pH meter, interface, and voltmeter
Kimwipes
Polyethylene wash bottle of distilled water
6- 150 ml beakers
400 ml beaker for waste
Procedure:
Electrode must remain in distilled water when not in use.
After each measurement, rinse electrode with distilled water.
Hint:
Discussion:
In the dissociation of sodium carbonate, carbonate anion reacts with water to give OH- thereby forming a basic solution:
CO32- + H2O ---> HCO3- + OH-
Similarily, in the dissociation of sodium acetate, acetate ion reacts with water to form OH-, thereby also giving a basic solution:
CH3COO- + H2O ---> CH3COOH + OH-
The hydrated ions of metals of small radius and high charge, like Fe3+ are stronger acids than water and donate protons to water molecules. The ferric nitrate solution is acidic:
Fe(H2O)63+ + H2O ---> Fe(H2O)5(OH)2+ + H3O+
To schedule a demonstration, please send an email to the demonstration lab.
Contact:
Eric Camp
Lecture Demonstration Technician
Bagley Hall 171
(206) 543-1606