Question

Write the balanced, net-ionic equations for the cell reactions for the following half-cell combinations at standard conditions. Be sure to consider direction of spontaneity.

A. Cu/Cu2+, Zn/Zn2+

B. Ag/Ag+, Mg/Mg2+

C. Zn/Zn2+, Pb/Pb2+

D. Ni/Ni2+, Ag/Ag+

E. Cu/Cu2+, Mg/Mg2+

Answer 1

A. Cu/Cu2+, Zn/Zn2+:

balanced, net-ionic equation

Zn (s) + Cu^2+ (aq)...............> Zn^2+ (aq) + Cu(s)

E0cell = 0.34 + 0.76 = 1.10 V

as E0cell is positive and hence this is spontaneous reaction.

B. Ag/Ag+, Mg/Mg2+:

balanced, net-ionic equation:

Mg (s) + 2 Ag+ (aq).................> Mg^2+ (aq) + 2 Ag(s)

As Mg is more reactive than Ag and hence this is spontaneous reaction.

C. Zn/Zn2+, Pb/Pb2+

balanced, net-ionic equation:

Zn (s) + Pb^2+ (aq) ...................> Zn^2+ (aq) + Pb (s)

As Zn is more reactive than Pb and hence this is spontaneous reaction.

D. Ni/Ni2+, Ag/Ag+

balanced net-ionic equation:

Ni (s) + 2 Ag+ (aq) ................> Ni^2+ (aq) + 2 Ag (s)
As Ni is more reactive than Ag and hence this is spontaneous reaction.

E. Cu/Cu2+, Mg/Mg2+

balanced net-ionic equation:

Mg (s) + Cu^2+ (aq)..............> Mg^2+ (aq) + Cu (s)

As Mg is more reactive than Cu and hence this is spontaneous reaction.