Ag^ + +NH_3 leftharpoons[Ag(NH_3)]^ + ; k_1=3.5 × 10^ -3...

(i) $\mathrm{Ag}^{+}+\mathrm{NH}_3 \rightleftharpoons\left[\mathrm{Ag}\left(\mathrm{NH}_3\right)\right]^{+} ; k_1=3.5 \times 10^{-3}$ (ii) $\left[\mathrm{Ag}\left(\mathrm{NH}_3\right)\right]^{+}+\mathrm{NH}_3 \rightleftharpoons\left[\mathrm{Ag}\left(\mathrm{NH}_3\right)_2\right]^{+}, k_2=1.7 \times 10^{-3}$ on the basis of above reaction $$\begin{aligned}& k_1=\frac{\left[\mathrm{Ag}\left(\mathrm{NH}_3\right)\right]^{+}}{\left[\mathrm{Ag}^{+}\right]\left[\mathrm{NH}_3\right]}\\ & k_2=\frac{\left[\mathrm{Ag}\left(\mathrm{NH}_3\right)_2\right]^{+}}{\left[\mathrm{Ag}\left(\mathrm{NH}_3\right)\right]^{+}\left[\mathrm{NH}_3\right]} \end{aligned}$$For the formation of \left[\mathrm{Ag}\left(\mathrm{NH}_3\right)_2\right]^{+}\mathrm{Ag}^{+}+$2$\mathrm{NH}_{3} \rightleftharpoons\left[\mathrm{Ag}\left(\mathrm{NH}_{3}\right)_2\right]^{+} Formation constant $(K)=\frac{\left[\mathrm{Ag}\left(\mathrm{NH}_3\right)_2\right]^{+}}{\left[\mathrm{Ag}^{+}\right]\left[\mathrm{NH}_3\right]^2}$ From eq. (i) and (ii) K=k_1 $\times$k_2=3.5 $\times$10^{-3} $\times$1.7 $\times$10^{-3}=5.95 $\times$10^{-6} $\approx$6.08 $\times$10^{-6}