Question

Water has no colour in the form of liquid or solid (ice) but in the form of snow why it is white.

Answer 1

The colour of an object is simply a combination of the frequencies of light it reflects. Blue objects seen in white light, for example are just objects that absorb all colours of the spectrum (from the incident white light) except blue and hence appear blue. 

Now, some objects just let all the light incident on them pass right through and they're calledtransparent objects. While some others partially reflect and partially let through incident light on them - called translucent objects. Light doesn't easily pass through ice but bounces around a lot and sometimes reflects back (which is why we see ice crystals sometimes having white patches in them)

Answer 2

Snow is a bunch of ice crystals stuck together. ... Snow reflects all the colors; no it doesn't absorb, transmit, or scatter any single color or wavelength more than any other. The “color” of all the light wavelengths combined equally is white.