5. To study the change in pH of acetic acid solution by addition of sodium acetate.

Aim:- To study the change in pH of acetic acid solution by addition of sodium acetate.

Requirements:- Test tubes, test tube stand, watch glass, pH paper, glass rod, acetic acid and sodium acetate for experiment.

Procedure:-

1. In a dry and clean test tube take 10 ml of acetic acid solution. Put a drop of this solution on a strip of pH paper and note it’s colour. Compare it with the colour on chart paper and note pH of the acid.
2. Now weight 1g of sodium acetate and put it in the tube containing acetic acid. Shake vigorously to dissolve sodium acetate. Determine pH of this solution with pH paper.
3. Weight again 1g of the sodium acetate, add to test tube and determine pH of this solution.
4. Repeat this with more of sodium acetate, and find out the change in pH value.

Observation:-

S. no.	Sample solution	Colour produced on pH paper.	Approximate pH value.
1.	CH3­COOH	Orange	2
2.	CH3COOH + 1g CH3COONa	Dark orange	3
3.	CH3COOH + 2g CH3COONa	Bright yellow	4
4.	CH3COOH + 3g CH3COONa	Yellow	5

Result:-

The pH value of solution goes on increasing on adding more and more sodium acetate.