Consider a concentration cell. Two Ag-electrodes are immersed inAgNO3 solutions of different concentrations. When the twocompartments have an AgNO3-concentration of 1 M and 0.1 M,respectively, the measured voltage is 0.065 V (note: T in notnecessarily = 25°C !).
a. What is the voltage, if the two compartmentshave AgNO3-concentration of 1 M and0.01 M, respectively?
The electrochemical behavior of silver nanoclusters (Agn, with nthe number of Ag atoms in the cluster) is investigated using thefollowing electrochemical cells at 298 K:
I. Ag(s) | AgCl (saturated) || Ag+(aq, 0.01M) |Ag(s), E=0.170
II. (Pt electrode) Agn (s, nanocluster) | Ag+(aq,0.01M) || AgCl (saturated) | Ag(s), with E = +1.030 V forAg5 nanocluster and E = +0.430 V for Ag10 nanocluster
The standard reduction potentialfor Ag+ + e- → Ag, is E0 = +0.800 V.
b. Use this data to calculate the solubility product ofAgCl.
The two nanoclusters Ag5 andAg10-nanoclusters have standard potentials different from thepotential of metallic bulk silver.
c. Calculate the standard potentials of Ag5 and of Ag10nanoclusters. [for this part use Ksp(AgCl)=1.800·10-5; this is notthe same value as calculated in b.]
d. What happens, if you put the Ag10 nanoclusters and –in a second experiment – the Ag5 nanoclusters into an aqueoussolution of pH=5? Estimate the consequences using the reductionpotentials you calculated.
