An octahedral coordination complex of cobalt(III) has the empirical formula CoCl ₃ x NH ₃ . When dissolved in water, one molecule of the complex dissociates to give a total of y ions. If it is known that this complex exhibits cis-trans isomerism, what is the value of x + y ?

Step-by-step solution

For cobalt(III), the typical coordination number is 6. Since the complex exhibits cis-trans isomerism and contains only monodentate ligands ( NH ₃ and Cl ^- ), its coordination sphere must be of the [ MA ₄ B ₂] type. Complexes of the type [ MA ₅ B ] or [ MA ₆] do not show geometrical isomerism. Thus, the formula of the complex must be [ Co ( NH ₃)₄ Cl ₂] Cl . Comparing this with the empirical formula CoCl ₃ x NH ₃ , we find that there are 4 ammonia molecules, so x = 4 . When dissolved in water, the complex ionizes