# The color of light absorbed by an aqueous solution of CuSO_"4" is??

${\text{Cu}}^{2 +}$ is blue in aqueous solution. ${\text{CuSO}}_{4}$ has a ${\lambda}_{\max}$ of about $\text{635 nm}$ (red). It reflects the color blue, so it absorbs mostly red light, the complementary color.