Question

For the following reaction, the equilibrium constant K_c at 298 K is 1.6 × 10¹⁷.

(${{\mathrm{Fe}}_{\left(\mathrm{aq}\right)}}^{2+}+{{\mathrm{S}}^{2-}}_{\left(\mathrm{aq}\right)}\rightleftharpoons \mathrm{FeS}\left(\mathrm{s}\right)$

When an equal volume of 0.06 M Fe⁺² and 0.2 M S^-2 solution are mixed, then the equilibrium concentration of Fe⁺² is found to be Y × 10^-17 M. Y is:

Answer 1

$$\begin{gathered} \mathrm{Solution}: \\ {\mathrm{Fe}}^{2+}+{\mathrm{S}}^{2-}\to \mathrm{FeS} \\ {\mathrm{K}}_{\mathrm{C}=1/\left(\mathrm{X}\right)[0.07]=1.6\times {10}^{17}} \\ \left[{\mathrm{Fe}}^{2+}\right]=8.928\times {10}^{-17} \\ \mathrm{y}\times {10}^{-17} \\ \mathrm{y}=8.93 \end{gathered}$$