Question

What is $pK$ value of the complex $\left[PtC{l}_4\right]$ if__________.
$P{t}^{4+}+C{l}^{-}\to [PtCl{]}^{3+}$ $K_1={10}^{-2}$
$[PtCl{]}^{3+}+C{l}^{-}\to [PtC{l}_2{]}^{2+}$ $K_2={10}^{-3}$
$[PtC{l}_2{]}^{2+}+C{l}^{-}\to [PtC{l}_3{]}^{+}$ $K_3={10}^{-4}$
$[PtC{l}_3{]}^{+}+C{l}^{-}\to [PtC{l}_4]$ $K_4={10}^{-4}$

Answer 1

On adding, $P{t}^{4+}+4C{l}^{-}\to PtC{l}_4$

$\therefore$ Overall stability constant $K=K_1{K}_2{K}_3{K}_4={10}^{-13}$
$logK=log{K}_1+log{K}_2+log{K}_3+log{K}_4=-13$

$-logK=13$

$pK=13$