[will_L]

how to draw the cell diagram of cl2.

Given e.m.f of the cell at standard conditions is +1.36v

reactions at the electrodes are: H(g) = (H+)(aq) + e

                                     and  Cl2(g) + (2e-) = (2Cl-)(aq)

giving an overall cell reaction :  Cl2(g) + H2(g) = (2Cl-)(aq) + (2H+)(aq)

[ramboacid]

I would guess that you would use platinum electrodes in both of the cells.
Pt|H₂, H⁺||Cl₂, Cl^-|Pt

http://en.wikipedia.org/wiki/Standard_hydrogen_electrode

[will_L]

yeah, but why is it Cl2(g) beside the salt bridge(//) instead of Cl- ? i thot the ions suppose to be next to the salt bridge.

[ramboacid]

yeah, but why is it Cl2(g) beside the salt bridge(//) instead of Cl- ? i thot the ions suppose to be next to the salt bridge.

I wrote the ions by the platinum electrode because that is where reduction occurs, at the cathode. The Cl₂ is reduced to Cl^- ions at the cathode and H₂ is oxidized to H⁺ at the anode.

I'm not very familiar with line notation for galvanic cells, so my notation might be wrong. I wrote it so that you could "read" the reaction from left to right (H₂ is oxidized to H⁺ and Cl₂ is reduced to Cl^-).

[will_L]

it is correct, cl2(g) and cl- shud be seen as a whole. thanks a lot.