Answer:
The colour of the sky during the day-time is blue because the molecules in the air scatter blue light more than the red light because the wavelength of the blue light is shorter than the other light.
During sunrise, the light rays coming from the Sun have to travel a greater distance in the earth’s atmosphere before reaching our eyes. In this journey, the shorter wavelengths of lights are scattered out and only longer wavelengths are able to reach our eyes. Since blue colour has a shorter wavelength and red colour has a longer wavelength, the red colour is able to reach our eyes after the atmospheric scattering of light.