Question

A transition metal complex in solution has an absorption peak at 450 nm, in the blue region of the visible spectrum. What color is this solution?
A) Violet B) Orange C) Green D) Blue

Answer 1

Answer:

In the case of a solution transition metal complex that has an absorption peak at 450 nm in the blue region of the visible spectrum, the (complementary) color of this solution is orange (option B).

Explanation:

The portion of UV-visible radiation that is absorbed implies that a portion of electromagnetic radiation is not absorbed by the sample and is therefore transmitted through it and can be captured by the human eye. That is, in the visible region of a complex, the visible color of a solution can be seen and that  corresponds to the wavelengths of light it transmits, not absorbs. The  absorbing color is complementary to the color it transmits.

So, in the attached image you can see the approximate wavelengths with the colors, where they locate the wavelength with the absorbed color, you will be able to observe the complementary color that is seen or reflected.

In the case of a solution transition metal complex that has an absorption peak at 450 nm in the blue region of the visible spectrum, the (complementary) color of this solution is orange (option B).