Question

why is water colourless?

Answer 1

Water means it s d  mixture of hydrogen and oxygen. As we know that hydrogen is colourless as well as oxygen is also colourless gas. 
So at last when hydrogen and oxygen reacts with one another and they form H2O means water. If both are colourless so their product will also be colourless. So water is seen colourless.

Answer 2

since water is only made up of gases oxygen and hydrogen which are colorless in nature , so water is also colorless. however water has the property to reflect so many a time we see the water as blue in large water bodies where water reflects the color of the blue sky above .

hope this helps you!!:)

PLEASE DO MARK AS THE BRAINLIEST!!!