选B。0.14V。Cu2+ + 2e- = CudeltaG'=-2Fx0.342) Cu+ + e- = Cu deltaG" =-Fx0.541)-2)得3):Cu2+ + e- = Cu+deltaG = -FE又,deltaG = deltaG'-deltaG"= -0.68F + 0.54F = -0.14F所以,E=0.14V
答案为B 考的是元素电势图 (Cu2+/Cu)=[(Cu2+/Cu+)+(Cu+/Cu)]/2
B:0.34,×2-0.54