Electrochemistry

Objectives A and B: Solutions

1.

Anode = site of oxidation; cathode = site of reduction

 

2.

The cathode uses up positive ions because it converts them to neutral elements. As a result, positive ions(cations) are converted to what's leftover : negative ions.

3.

A. yes

B. yes

C. The reverse reaction because Cu > Fe+2 >Au, where Cu = strongest oxidation agent.

D. Au+3 is the strongest oxidizing agent (electron mugger) in this example.

4.
  1. Li
  2. Li
  3. 3 Li + Al+3 --> 3Li+1 + Al
  4. Al+3 > Li+1

5.

  1. Cr|| Cr+3||Au+3||Au
  2. Anode cathode
  3. Electrons --->
  4. Cr --> Cr+3 + 3e

Au+3 + 3e --> Au

6. p515 text

(1)2 Al + 3Cu+2 --> 2Al+3 + 3Cu; E = 2.00 V

(2) Cu + 2 Ag+1 --> Cu+2 + 2Ag; E = 0.46 V

(3) Co+2 + 2e --> Co E = -0.28 V

Fe --> Fe+2 + 2e E = +0.44V

Overall: Co+2 + Fe-->Co + Fe+2 E = 0.16V

(4) a. nonspontaneous; E = -0.34V

b. nonspontaneous; E = -1.24V

c. nonspontaneous; E = -0.02V