Properties of Pure Water:

Odourless:
Pure water is odourless, which means it does not have any smell. This is because pure water does not contain any impurities or substances that could produce a scent.

Tasteless:
Pure water is tasteless, which means it does not have a distinct flavor. This is because pure water does not contain any dissolved substances that could give it a taste. It does not have any sweetness, bitterness, or any other flavor characteristic.

Colorless:
Pure water is colorless, meaning it does not have any color. It appears transparent and clear to the naked eye. This is because pure water does not contain any substances that would absorb or reflect light to create a color.

Explanation:
All three statements, a) Pure water is odourless, b) Pure water is tasteless, and c) Pure water is colorless, are correct for pure water.

Water is considered pure when it contains no impurities, contaminants, or dissolved substances. Pure water is made up of hydrogen and oxygen molecules and does not have any additional substances that would give it a smell, taste, or color.

The absence of odor in pure water is due to the fact that it does not contain any substances that could release volatile compounds or produce a scent. Similarly, the absence of taste in pure water is because it does not have any dissolved substances that could stimulate taste receptors on the tongue. Lastly, the colorlessness of pure water is a result of its molecular structure, which does not allow for the absorption or reflection of light that would create a color.

Therefore, the correct answer is option 'D' - all of these statements are true for pure water.

D