As ethylenediamine is added to an aqueous solution of [Ni(H2O)6]2+, the water molecules are replaced two at a time by ethylenediamine to produce the sequence of ions: [Ni(H2O)6]2+, [Ni(en)(H2O)4]2+,[Ni(en)2(H2O)2]2+, and[Ni(en)3]2+. How does the color change through the sequence?
◦ The color changes toward red with the addition of ethylenediamine.
◦ The color changes toward purple with the addition of ethylenediamine.
◦ Red, yellow, purple, blue with the addition of ethylenediamine.
◦ There is no color change with the addition of ethylenediamine.
◦ The color change cannot be predicted with the addition of ethylenediamine.