The true statement is (A) energy is absorbed during the reaction
For the products to have more energy, they must absorb it from the surrounding.
The solubility of potassium chloride in at room temperature is approximately 34 g per 100 g of water. Therefore, the maximum amount that could be dissolved would be 34/100 ( 200) = 68 g of KCl. When more than this amount is added, excess potassium would not dissolve forming crystals in the solution.
For [Ni(en)³]²⁺ which is purple, the crystal field splitting energy is greater than the complex ion, [Ni(H₂O)₆]²⁺ which is green in color.
When a Lewis base id attached to the metal ion by covalent bond, then the complex ion is formed and when these complex ions are present with other ions of opposite charge or neutral charge, they will make complex compounds.