Question

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)

Answer 1

Answer: Silver (Ag) will be produced at the cathode.

Step-by-step explanation:

Ag ihas the highest reduction potential being lowest in the electrochemical series

Answer 2

Ag(s)

Step-by-step explanation:

Let us examine the reduction potentials of all the metals listed:

Mg= -2.37V

Cu=+0.34V

Ag= +0.80V

Ni= -0.25V

Looking at the information above, it is clear that silver, having the most positive reduction potential will be discharged at the cathode among the mixture of cations present. Hence the answer.