Compare the pH of solutions of hydrochloric acid and acetic acid having same concentration.
Test tubes, glass rod, universal indicator solution, 0.1 M HCl, 0.01 M HCl, 0.1 M CH3COOH and 0.01 M CH3COOH.
A strong acid is completely ionised in aqueous solution. It produces higher conccentration of hydrogen ions for a given concentration of the acid as compared with a weak acid and hence has lower pH.
1. Take four clean and dry test tubes and half fill each of the tubes with one of the acid solutions.
2. Add 3-4 drops of universal indicator to each test tube and swirl the solutions until the colours are uniform.
3. Compare the colour of each solution with the â€˜pH indicator chart’ and estimate the pH of each solution and record the observations in the data table.
Observations And Results
|Solution||Colour produced in the solution
by universal indicator
|0.1 M HCl
0.1 M CH3COOH
|0.01 M HCl
0.01 M CH3COOH
The pH of a solution of HCl (a strong acid) is lower than the pH of a solution of CH3COOH (a weak acid) having same concentration.