6. To study the change in pH of ammonium hydroxide solution by the addition of ammonium chloride.

Aim:- To study the change in pH of ammonium hydroxide solution by the addition of ammonium chloride.

Requirements:- Test tube, test tube stand, watch glass, pH paper, glass rod, ammonium hydroxide and ammonium chloride for experiment.

Procedure:-

1. Take 10 ml of ammonium hydroxide solution in a test tube. Put a drop of this on pH paper and not the colour. Compare the colour produced with the colour on chart paper and note it, pH value.
2. Now weight 1.5g os NH₄Cl and out in the tube containing NH₄OH. Shake vigorously and note the pH with the help of pH paper.
3. Repeat the experiment by addition two more 1g of NH₄Cl. Note if there is any change in pH value.

Observation:-

S. No.	Sample Solution	Colour produced on pH paper	Approximate pH value
1.	NH4OH	Purple	12
2.	NH4OH + 1g NH4Cl	Dark blue	11
3.	NH4OH + 2g NH4Cl	Blue	0
4.	NH4OH + 3g NH4Cl	Blue	10

Result:-

The pH of NH₄OH decreases with addition of NH₄Cl to it.