A solution contains . If is added to make the total concentration , what is the final ? () — Ionic Equilibrium Chemistry Question

💡 Solution & Explanation

For $H_2S$, overall $K = K_1 K_2 = [H^+]^2[S^{2-}]/[H_2S] = 10^{-21}$. Since $H^+$ is fixed at 0.1 M by HCl and $[H_2S] \approx 0.1 \text{ M}$, $(0.1)^2[S^{2-}] / (0.1) = 10^{-21} \implies [S^{2-}] = 10^{-20} \text{ M}$.