[Al1ygator]

Hi!
I have a question relating to electrolysis. The two quetsions in my book (zumdahl & zumdahl) are:

87. What reactions take place at the cathode and the anode when each of the following is electrolyzed?
a. molten NiBr2
b. molten AlF3
c. molten MnI2

88. What reactions take place at the cathode and the anode when each of the following is electrolyzed? (assume standard conditions)
a. 1.0M NiBr2 solution
b. 1.0M AlF3 solution
c. 1.0M MnI2 solution


My question is how are they different? I understand why for molten NiBr2 the anode is 2Br- to Br2 + 2e and why the cacthode is Ni+2 + 2e to Ni, but then 88 confuses me....would it be the same?

Thanks a bunch!
~Allison

[Garneck]

No, because it's a solution. You'll get hydrogen on the cathode.

[Al1ygator]

thanks! so would oxygen be at the anode? or would it be one of the ions?

[Garneck]

No. You will get the halogen gas.

C: 2H+ + 2e = H2
A: 2X- = X2 + 2e