How to know If water is clean or contaminated

Question

I need specific information. Its for my science investigatory project.

thanks in advance

Answer 1

There are many ways, but any single method alone would not be able to establish the conclusion of clean water.

1. Measure the pH.  Pure water would have a pH value of 7.00.  However, CO2 from air dissolution into water would gradually reduce pH to a value between 5 to 6.  It the pH of your water sample should be too high or too low, it is contaminated.

2. Boil some of the water sample to dry.  Any solid precipitation would indicate contaminated water.  However, small amount of volatile impurity such as HCl would not be detected this way.

3. Measure the freezing point and the boiling point very accurately.  The freezing point and the boiling point of pure water at one atm should be 0.00C and 100C.  Any change in either of them would indicate the water sample to be contaminated.

4. There are many more measurements such as osmotic pressure, density, vapor pressure, (IR, vis, UV, Raman) spectroscopies, etc, can be used to check evidences of the contamination.