## 14.13 part d

Teresa Chan 2G
Posts: 9
Joined: Wed Sep 21, 2016 2:57 pm

### 14.13 part d

How do we write the half reactions for $Au^+(aq)\rightarrow Au(s)+Au^{3+}(aq)$ and the cell diagram for this? I know the solutions manual gives the answer but I'm still confused as to how to do it

Audrey Magsig 1E
Posts: 17
Joined: Wed Sep 21, 2016 3:00 pm

### Re: 14.13 part d

For the half reactions, you know that Au is going to be both oxidized and reduced. Break it up into the half reactions then:

Au+(aq) ->Au (s)
Au+(aq) ->Au 3+ (aq)

then calculate the oxidation numbers:
Au+: +1
Au(s): 0
Au 3+: +3

Balance the overall oxidation numbers on both sides of the reaction by adding electrons:

Au+(aq) + e ->Au (s)
Au+(aq) ->Au 3+ (aq) + 2e

For the cell diagram anode goes on the left, cathode goes on the right with a double line to separate. If there are phase changes on either side between the reactants and the products, you add a single line, otherwise use a comma:

anode II cathode

Au+(aq), Au 3+ (aq) II Au+(aq) I Au (s)

If there is no presence of a solid forming, use Pt as the inert electrode:

Pt(s) I Au+(aq), Au 3+ (aq) II Au+(aq) I Au (s)