Chemicals and Solutions:
95% ethanol
Distilled water
Sodium chloride (1M)
Sodium hydroxide (1M)
Hydrochloric acid (1M)
Acetic acid (1M)
Ammonium hydroxide (1M)
Materials:
Multiple conductivity apparatus
7 - 250 ml beakers
Procedure:
Label 7 beakers to contain the above listed solution
3/4 fill each beaker with the appropriate solution
Remove the top of the conductivity apparatus carefully and place each solution in its designated place.
Replace top carefully.
Push the button on top to check the conductivity of each solution.
Discussion:
When NaCl, HCl, and NaOH react with water they are completely converted to ions. Therefore their solutions have high electrical conductivity and the light bulb is lit up very brightly. Ammonium Hydroxide and Acetic acid react incompletely with water; they are not completely ionized. Therefore their solutions have only a small electrical conductivity and the light bulb glows dimly. Ethanol and water have covalent bonds and do not conduct electricity.
To schedule a demonstration, please send an email to the demonstration lab.
Contact:
Eric Camp
Lecture Demonstration Technician
Bagley Hall 171
(206) 543-1606