A chemical compound that appears white is one that reflects all the light falling on it and does not absorb light of any color. A beam of light that has the frequencies of light of the seven constituent colors generally represented as violet, indigo, blue, green, yellow, orange and red is white in color.
Colorless substances are transparent in nature. They allow light falling on them to pass through and neither absorb light of any color nor reflect the light of any color back.
Lead chloride of PbCl is white in color.
Lead sulphate or PbSO4 is also white in color.
Silver chloride or AgCl is white in color.
Silver sulfate or AgSO4 is black in color.