Question

A current is applied to two electrolytic cells in series. In the first, silver is deposited; in the second, a zinc electrode is consumed. How much Ag is plated out if 1.2 g of Zn dissolves?

Short answer

The amount of Ag plated out is obtained as: $\text{3.96 g Ag}$

Step-by-step solution

Define chemical reaction

Chemical synthesis or, alternatively, chemical breakdown into two or more separate chemicals occurs when one component interacts with another to generate new material. These processes are known as chemical reactions, and they are generally irreversible until followed by other chemical reactions.

Step 2: How much Ag is plated out if 1.2  g of Zn dissolves?

The reactions being identified are:

$$\begin{gathered} {\text{Ag}}^{\text{+}}{\text{+e}}^{\text{-}}\to \text{Ag} \\ \text{Zn}\to {\text{Zn}}^{\text{2 +}}{\text{+ 2e}}^{\text{-}} \\ {\text{2Ag}}^{\text{+}}\text{+ Zn}\to {\text{2Ag + Zn}}^{\text{2 +}} \end{gathered}$$

Two moles of Ag are generated for every mole of Zn that reacts.

Using the molar ratio, convert the quantity of Zn dissolved to the mass of Ag produced.

$\text{1.2 g Zn×}\frac{{\displaystyle \text{1 mol Zn}}}{{\displaystyle \text{65.38 g Zn}}}\text{×}\frac{{\displaystyle \text{2 mol Ag}}}{{\displaystyle \text{1 mol Zn}}}\text{×}\frac{{\displaystyle \text{107.9 g Ag}}}{{\displaystyle \text{1 mol Ag}}}\text{= 3.96 g Ag}$

Therefore, the value is $\text{3.96 g Ag}$.