**10points** Reactions at Electrodes during Electrolysis?

Please help! I cant figure out how to do these, please explain. :)

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 1.0 M AgNO3?

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

Ag --> Ag+ + e-

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

Ag+ + e- --> Ag

Which half-reaction will take place at the anode during the electrolysis of 0.10M aqueous KF solution?

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

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

K+ + e- --> K

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

Which half-reaction will take place at the cathode during the electrolysis of molten KF?

2F- --> F2 + 2e-

F2 + 2e- --> 2F-

K --> K+ + e-

K+ + e- --> K

Which half-reaction will take place at the cathode during the electrolysis of 0.10M aqueous KF solution?

2F- --> F2 + 2e-

K --> K+ + e-

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

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