Question

In the laboratory you are given the task of separating Ag+ and Cu2+ ions in aqueous solution.

For each reagent listed below indicate if it can be used to separate the ions. Type "Y" for yes or "N" for no. If the reagent CAN be used to separate the ions, give the formula of the precipitate. If it cannot, type "No"


Y or N Reagent Formula of Precipitate if YES

1. NaI

2. K2S

3. K2CO3

Answer 1

1. NaI Y AgI

2. K2S Y CuS

3. K2CO3 N

Step-by-step explanation:

1. When we add NaI to the mixture, the reaction that takes place is:

• NaI(aq) + Ag⁺(aq) → AgI(s) + Na⁺(aq)

Such a reaction does not happen with Cu⁺².

2. When we add K₂S to the mixture, the reaction that takes place is:

• K₂S(aq) + Cu⁺²(aq) → CuS(s) + 2K⁺(aq)

Such a reaction does not happen with Ag⁺.

3. When we add K₂CO₃ to the mixture, the reactions that take place are:

• K₂CO₃(aq) + 2Ag⁺(aq) → Ag₂CO₃(s) + 2K⁺(aq)

• K₂CO₃(aq) + Cu⁺²(aq) → CuCO₃(s) + 2K⁺(aq)

This means both Cu⁺² and Ag⁺ would precipitate, thus they would not be separated.