To check the pH of tap water and compare it with pH of the water in the local water body.
Apparatus : Test tubes or beaker
Materials : Universal pH indicator / litmus paper
Procedure :
`implies ` Take water sample from tap of your home in a test tube.
` implies` Add few drops of the universal indicator into the test tube containing tap water.
`implies` Observe the water sample in the test tube for colour change.
`implies ` Test pH using a litmus paper, in the water sample placed in a beaker.
`implies ` Dip the litmus paper into the water in the local water body.
`implies` Observe colour changes of the litmus paper.
Observation :
`implies` Test tube containing tap water, turns yellow colour with addition of pH indicator.
`implies` Litmus paper does not show colour change with tap water.
`implies` Water sample collected from pond shows red colour with pH indicator. Litmus paper turns red as it is dipped in water of local water body.
Conclusion :
The uncontaminated tap water is neutral while water of local water body is acidic.
Can you say whether the water is polluted or not on the basis of your observations?

Explanation

Yes, tap water is clean and non-polluted. Water of water body is polluted.