Standard Reduction Principal?

Half Reaction Eo (V)


Zn2+(aq) + 2e- -%26gt; Zn(s) = –0.763


Tl+(aq) + e- -%26gt; Tl(s) = –0.336





Use the standard reduction potentials to find the standard


cell potential, E°, for the reaction;


Zn(s) + 2Tl+(aq) r Zn2+(aq) + 2Tl(s)


(A) 0.427 V (B) 0.091 V


(C) –0.091 V (D) –0.427 V


How would I solve this?

Standard Reduction Principal?
Zn2+(aq) + 2e- -%26gt; Zn(s) = –0.763


Tl+(aq) + e- -%26gt; Tl(s) = –0.336





Flip first equation





Zn(s) -%26gt; Zn2+(aq) + 2e- = +0.763


Tl+(aq) + e- -%26gt; Tl(s) = –0.336





Note sign change





Mult. 2nd equation by 2





Zn(s) -%26gt; Zn2+(aq) + 2e- = +0.763


2Tl+(aq) + 2e- -%26gt; 2Tl(s) = –0.336





Note that the voltage is unaffected.





Add equations and voltages together. Here is just the voltages:





+0.763 + (-0.336) = 0.427 V