Explanation

(a)
1.$\left\lbrack Cu\left( NH_{3} \right)_{4} \right\rbrack\lbrack PtCl_{4}\rbrack$
2.$\left\lbrack Cu\left( NH_{3} \right)_{3}Cl \right\rbrack \bullet \lbrack PtCl_{3}({NH}_{3})\rbrack$
3.$\left\lbrack Cu\left( NH_{3} \right)_{2} \right\rbrack \bullet \left\lbrack PtCl_{2}\left( {NH}_{3} \right)_{2} \right\rbrack\ cis$
4.$\left\lbrack Cu\left( NH_{3} \right)_{2}{Cl}_{2} \right\rbrack\left\lbrack PtCl_{2}\left( {NH}_{3} \right)_{2} \right\rbrack\ trans$
5.$\left\lbrack Cu{\left( NH_{3} \right)Cl}_{3} \right\rbrack \bullet \lbrack Pt(C{l)({NH}_{3})}_{3}\rbrack$
6.$\left\lbrack Pt\left( NH_{3} \right)_{4} \right\rbrack \bullet \lbrack CuCl_{4}\rbrack$