Rationalize how the addition of the silver nitrate to the Fe/SCN equilibrium system had an effect even though neither Ag nor NO3 appears in the equation shown in the text. Equation in text is FE3+ + SCN- [FeSCN]2+. I know that AgSCN is formed and precipitates and that equilibrium shifts to the left.

Question

Rationalize how the addition of the silver nitrate to the Fe/SCN equilibrium system had an effect even though neither Ag nor NO3 appears in the equation shown in the text. Equation in text is FE3+ + SCN- <> [FeSCN]2+. I know that AgSCN is formed and precipitates and that equilibrium shifts to the left.

DrBob222 · Answer

You have the answer. What else is to explain? The AgSCN ppts, the SCN concn is decreased, the reaction shifts to the left to compensate and less FeSCN^2+ complex is formed.