Determine the pH of solutions of some salts using pH paper or universal indicator
Test tubes, measuring cylinder, glass rod, pH paper, universal indicator solution, 0.1 M and
0.01 M solutions of some salts.
1. Using pH Paper. Take a strip of pH paper and put 1-2 drops of the first salt solution on it with the help of a glass rod. Observe the colour on the pH paper. Compare, the colour of the pH strip with the ‘pH indicator chart’ and estimate the pH of the solution.
Repeat the process with different salt solutions and record the observations in the data table.
2. Using Indicator Solution. Take some clean and dry test tubes and put about 5.0 mL of one of the salt solutions in each test tube. Now add 3-4 drops of universal indicator solution to each test tube by means of a dropper. Swirl the solutions until the colours become uniform.Compare the colour of each solution with the ‘pH indicator chart’ and estimate the pH of the solution.
Observations And Results
Approximate pH of Some Salt Solutions
|Salt Solution||For pH paper||For indicator solution|
|Colour produced on pH paper||Approximate|
|Colour produced in solution||Approximate|
|0.1 M CH3COONa|
0.01 M CH3COONa
|0.1 M Na2C03 |
0.01 M Na2C03
|0.1 M FeCl3 |
0.01 M FeCl3
|0.1 M BaCl2 |
0.01 M BaCl2
|o.1 M NaCl|
0.01 M NaCl
|0.1 M NH4Cl|
0.01 M NH4Cl
|0.1 M (NH4)3PO4 |
0.01 M (NH4)3PO4
The aqueous solutions of salts of weak acids and strong bases have pH ….. .
The aqueous solutions of salts of strong acids and weak bases have pH …… .
The aqueous solutions of salts of strong acids and strong bases have pH …… .
The aqueous solutions of salts of weak acids and weak base have pH ……. .