Hazards:
Concentrated solutions of HCl are corrosive and toxic
Chemicals and Solutions:
0.1 M HCl
Methyl orange indicator solution
Materials:
5 cylinders
100 ml graduated cylinder, 10 ml grad. cylinder
Buffer array of methyl orange indicator
stir rods
pH meter and digital display
Procedure:
Mark cylinders as follows: 0.1 M, 0.01 M, 10-3 M, 10-4 M, 10-5 M Hydrochloric acid.
Fill the first cylinder (marked 0.1 M) with 100 ml of 0.1 M HCl.
Measure 10 ml of 0.1 M HCl into 100 ml cylinder, dilute to 100 ml with distilled water.
Repeat the above step, making a serial dilution, until all the concentrations have been made.
Add methyl orange indicator to each concentration and compare color to the buffer array. Use the pH meter-digital display to take the pH of each concentration.
Hint:
This demonstration can be used in conjunction with demonstration # 58 Weak acids: pH of acetic acid
To schedule a demonstration, please send an email to the demonstration lab.
Contact:
Eric Camp
Lecture Demonstration Technician
Bagley Hall 171
(206) 543-1606