How would you confirm that a colourless liquid given to you is pure water?

Confirming the purity of water, especially when it is a colorless liquid, involves several methods. Here are some common approaches:

1. Physical Observation:
– Observe the physical characteristics of the liquid. Pure water should be clear and colorless. Any deviation from this may indicate impurities.

2. Smell Test:
– Pure water is odorless. If the liquid has any unusual or distinct smell, it might contain impurities.

3. Boiling Point:
– Pure water boils at 100 degrees Celsius at standard atmospheric pressure. You could heat the liquid and check if it boils at the expected temperature.

4. Freezing Point:
– Pure water freezes at 0 degrees Celsius. If you have access to a freezer, you could check if the liquid freezes at this temperature.

5. Conductivity Test:
– Pure water is a poor conductor of electricity. Using a conductivity tester, you can check if the liquid conducts electricity. If it does not, it suggests high purity.

6. pH Testing:
– Pure water has a neutral pH of 7. You can use pH strips or a pH meter to test the acidity or alkalinity of the liquid.

7. Distillation:
– Distillation is a more advanced method. You could distill the liquid and collect the condensed vapor. If the distillate is also colorless and has the expected properties of pure water, it indicates high purity.

8. Chemical Analysis:
– More sophisticated methods involve laboratory testing, such as chromatography or spectroscopy, to analyze the composition of the liquid at a molecular level.