Question

Reactions at Electrodes during Electrolysis Answer the following questions by selecting the appropriate half-reaction. Assume that in each case the experiment is performed in an electrolysis cell having electrodes made of non-reacting material. Which half-reaction will take place at the cathode during the electrolysis of 0.10M aqueous KF solution? O 2H20 + 2e - H2 + 20H O 02 + 4H+ + 4e + 2H20 O 2H20 02 + 4H+ + 4e OK → K+ + e Which half-reaction will take place at the anode during the electrolysis of 1.0 M AgNO3? O 2H20 02 + 4H+ + 4e Ag+ e + Ag O 2H20 + 2 H2 + 2OH- O Ag - Ag+ + Which half-reaction will take place at the anode during the electrolysis of 0.10M aqueous KF solution? O 2H20 + 2 H2 + 2OH- 2H20 02 + 4H+ + 4e- O K+ + e +K O2F — F2 + 2e which half-reaction will take place at the cathode during the electrolysis of molten KF? O F2 + 2e - →2F O K+ + e K OK + K+ + e O2F + F2 + 2e Submit Answer Incorrect. Tries 2/5 Previous Tries

Previous Tries were:

1st Try:
2H2O --> O2 + 4H+ + 4e-   
Ag --> Ag+ + e-   
2F- --> F2 + 2e-   
F2 + 2e- --> 2F-
Second Try:
O2 + 4H+ + 4e- --> 2H2O   
Ag --> Ag+ + e-   
2H2O --> O2 + 4H+ + 4e-   
F2 + 2e- --> 2F-

Answer 1

During the electrolysis ,

reduction takesplace at cathode and oxidtion at anode.

1) electrolysis of 0.100 aqueous KF

here both water and KF are present

As the discharge potential of H+ to H2 is less than that of K+ , at cathode H2 is liberated NOT K.

So reduction of H2O at cathode.

2H2O +2e- ------------> H2 + 2OH-

Q2)

1.0M AgNO3

At anode H2O is oxidised O2 as NO3- has very high reduction potential than H2O.

The reaction is

2H2O -----> O2 + 4H+ + 4 e-

Q3)

At anode oxidation of water (or OH-) to O2 takesplace as F- has higher potential than OH-.

Thus oxidation at anode is

2H2O -----> O2 + 4H+ + 4 e-

Q4)with molten KF

at cathode the only cation is K+ that can be reduced.

So the reduction half reaction at cathode is

K+ + e- -----> K