Question

Solutions of [Cr(OH2)6]3+ ions are pale greeny-blue but the

chromate ion, [CrO4]2−, is an intense yellow. Characterize the
origins of the transitions and explain the relative
intensities.

Answer 1

The pale greeny-blue color of [Cr(OH2)6]3+ ions is due to the presence of complex ions. The intense yellow color of [CrO4]2- is also due to complex ions. The relative intensities depend on concentration and absorbance.

Step-by-step explanation:

The pale greeny-blue color of solutions containing [Cr(OH2)6]3+ ions is due to the presence of complex ions in solution. The complex ion [Cr(OH2)6]3+ absorbs specific wavelengths of light, reflecting a pale greeny-blue color back to our eyes.

On the other hand, the intense yellow color of the chromate ion [CrO4]2- is also due to the presence of complex ions in solution. The chromate ion absorbs specific wavelengths of light, reflecting an intense yellow color back to our eyes.

The relative intensities of the colors are determined by the concentration and absorbance properties of the complex ions. The higher the concentration and the higher the absorbance of light, the more intense the color will appear.