What does the dispersal of white light give?

the colors of the visible spectrum. White light can be split up to form a spectrum using a prism.

It will give the visible colours of the e-m spectrum and depending on the source it will also split off the infra red and ultra-violet components also.

Dispersion of light is the splitting of white light into its constituent colors due to the refractive index of the surface and the wavelength of the light.