${\left[\mathrm{Ti}{\left({\mathrm{H}}_2\mathrm{O}\right)}_6\right]}^{3+}$ absorbs green and yellow region part of visible light. Then the transmitted colour of the compound is

We know that white light is composed of many different colours. When white light is allowed to fall on ${\left[\mathrm{Ti}{\left({\mathrm{H}}_2\mathrm{O}\right)}_6\right]}^{3+}$ ion, this ion absorbs the light of green and yellow colour and transmits is almost purple colour. The purple colour of the transmitted light is called complimentary colour of that of absorbed light.