Question

The colour of light absorbed by an aqueous solution of $CuS{O}_4$ is:

• A. Orange – red
• B. Blue – green
• C. Yellow
• D. Violet

Answer 1

The correct option is A Orange – red

The colour visible to the human eye is a complementary result of the colour absorbed.
Copper sulphate is blue in aqueous solution. This means the complementary colour of blue is absorbed which we know to be closer to red. Thus, we can say that an orange-red wavelength is absorbed by the solution.