The concentration of in the original saturated solution was — Ionic Equilibrium Chemistry Question

💡 Solution & Explanation

The reaction $\text{Cu(s)} + 2\text{Ag}^+\text{(aq)} \rightleftharpoons \text{Cu}^{2+}\text{(aq)} + 2\text{Ag(s)}$ has a highly negative $\Delta G^\circ$, meaning the equilibrium constant is extremely large, and the reaction proceeds almost completely to the right. The $1.0 \times 10^{-4}\text{ moles}$ of Cu consumed reacts with exactly twice that amount of $\text{Ag}^+$ ions. So, moles of $\text{Ag}^+$ consumed = $2 \times 1.0 \times 10^{-4} = 2.0 \times 10^{-4}\text{ moles}$. Because the reaction goes to completion and volume is 1 L, the original concentration of $\text{Ag}^+$ in the saturated solution was $2.0 \times 10^{-4}\text{ M}$. Therefore, correct answer is C.