Asked by Sarah

This is the question I am having trouble with:

A voltaic cell consists of a strip of lead metal in a solution of Pb(NO3)2 in one beaker, and in the other beaker a platinum electrode is immersed in a NaCl solution, with Cl2 gas bubbled around the electrode. A salt bridge connects the two beakers.

I have already figured out that the
--anode is: Pb
--cathode is: Pt
--and that the Pb electrode loses mass as the cell reaction proceeds.

I am having trouble writing "overall cell reaction"
(c) Write the equation for the overall cell reaction. (Use the lowest possible coefficients. Include states-of-matter under SATP conditions in your answer.)
and
(d) What is the emf generated by the cell under standard conditions?

But I realize that I first need to get the correct reaction before I can do part D. If you can help me out that would be much appreciated! Thank You!!
Answered by DrBob222
If you know the anode and cathode already you can get the reaction from that. At the anode you have
Pb ==> Pb^+ + 2e
At the cathode you have
Cl2 + 2e ==> 2Cl^-
Add the two half equations for the cell reaction. You can add the phases.
Answered by Sarah
Hi Dr. Bob222
Thank you so much for replying! I actually have already tried this equation...

Pb(s) + Cl2(g) --> Pb^2+(aq) 2Cl^-(aq)

and it said it was wrong

So that is why I am confused. Because I was initially solving it the way you had written the half reactions and then joining it together.
Answered by DrBob222
I don't know. I don't think it can be PbCl2 forming since the two beakers are connected only with a salt bridge. The cathode surely must be the Cl2 since the Pt is an inert electrode and no conditions are given for the H2O there (that is I don' think we would worry about the H2O reacting). That is the 2H2O + O2 + 4e --> 4OH^-
If you submitted the answer exactly as you posted it to me there is a + sign missing in the products and that could acount for the database saying it was wrong; however, I'm sure that's just a typo.
If that error message persists, I don't know where they are going. Sorry about that.
Answered by Sarah
It turns out I had entered it in wrong! Thank you so much for your help! I really appreciate it!
Answered by DrBob222
whew! I'm glad I didn't goof.
Answered by Tess
You typed the anwser in mixed around. It should be Cl2+Pb--->[Pb}2+(aq)+2[Cl]-
There are no AI answers yet. The ability to request AI answers is coming soon!