When electricity is applied to a molten binary salt, the cation will be reduced and the anion will be oxidized. The electrolysis of CaBr2(l), for example, produces Ca(s) at the cathode (from the reduction of Ca2+) and Br2(l) at the anode (from the oxidation of Br-).
If more than one cation is present, only the one with highest reduction potential will be reduced. Similarly, if more than one anion is present, only the one with the highest oxidation potential will be oxidized.
Electrolysis is performed on a mixture of CuBr(l), AgBr(l), MgBr2(l), and NiBr2(l). Which of the following is produced at the cathode?
a) Br2(l)
b) Cu(s)
c) Ag(s)
d) Mg(s)
e) Ni(s)
c) silver
I would look up the reduction potentials of the cations and find the highest.
thanks saizad
To determine which substance is produced at the cathode during the electrolysis of the given mixture, we need to compare the reduction potentials of the cations present.
The reduction potentials of Cu2+, Ag+, Mg2+, and Ni2+ can be found in a reference table, such as a standard reduction potentials table.
The highest reduction potential among the cations is Cu2+ (copper) with a reduction potential of +0.34 V. This means that Cu2+ has the highest tendency to be reduced.
Therefore, during electrolysis, Cu2+ will be reduced to Cu(s) at the cathode.
Hence, the correct answer is (b) Cu(s).