Chapter 19, Problem 2SEPP

A galvanic cell is constructed by immersing a piece of copper wire in 25.0 mL of a $\text{0}\text{.20 }M{\text{ CuSO}}_{\text{4}}$ solution and $\text{0}\text{.20 }M{\text{ ZnSO}}_{\text{4}}$ solution. ${\text{Cu}}^{\text{2+}}$ ions react with aqueous ${\text{NH}}_{\text{3}}$ to form the complex ion $\text{Cu}{\left(\text{NH3}\right)}_4^{2+}$ :

${\text{Cu}}^{\text{2+}}\text{(}aq{\text{)+4NH}}_{\text{3}}\text{(}aq\text{)}\underset{}{\to }\text{Cu}{\left({\text{NH}}_{\text{3}}\right)}_4^{2+}(aq)$

What would happen if a small amount of concentrated ${\text{NH}}_{\text{3}}$ solution were added to the ${\text{CuSO}}_{\text{4}}$ solution?

a)

Nothing.

b)

Emf would increase.

c)

Emf would decrease.

d)

Not enough information to determine.