Question

reaction of change in color

Answer 1

The colour change can occur because of many factors:

The change in reactant state and conditions.

Molecular interaction.

Light, temperatures, pressure changes.

For example, CuSO4 is white while, CuSO4.5H2O is blue. As the water comes(or any ligand), the orbitals of Cu2+ undergo a change, leading to possibility of absorption and re-emittance of light in visible spectrum.