In: Chemistry
A voltaic cell is constructed from an Ni2+(aq)−Ni(s) half-cell and an Ag+(aq)−Ag(s) half-cell.The initial concentration of Ni2+(aq) in the Ni2+−Ni half-cell is [Ni2+]= 1.80×10−2 M . The initial cell voltage is +1.13 V .
1. By using data in Table 20.1 in the textbook, calculate the standard emf of this voltaic cell.
Ni(s) --------------> Ni^2+ + 2e^- E0 = 0.23v
2Ag^+(aq)+ 2e^- ----------> 2Ag(s) E0 = 0.80v
-----------------------------------------------------------------------
Ni(s) + 2Ag^+(aq) ---------------> 2Ag(s) + Ni^2+ (aq) E0cell = 1.03v
n= 2
Ecell = E0cell -0.0592/n logQ
Ecell = E0cell- 0.0592/2 log[Ni^2+]/[Ag^+]^2
1.13 = 1.03 -0.0296log0.018/[Ag^+]^2
1.13-1.03 = -0.0296log0.018/[Ag^+]^2
-0.1/0.0296 = log0.018/[Ag^+]^2
log0.018/[Ag^+]^2 = -3.3783
0.018/[Ag^+]^2 = 10^-3.3783
0.018/[Ag^+]^2 = 0.0001485
[Ag^+]^2 = 0.018/0.0001485
[Ag^+]^2 = 121.2
[Ag^+] = 11M >>>>>answer