A spontaneous reaction is one in which the change in free energy is negative and the standard cell potential is positive.
For a redox reaction to be spontaneous, the electrode potential of the cell must be positive and this depends on the relative electrode potentials of the species involved in the reaction. A metal can not displace a metal above it in the electrochemical series from solution.
Based on this;
- Fe2+ (aq) + Al (s) → Al3+(aq) + Fe (s) is spontaneous because iron is lower than aluminium in the electrochemical series
- Pb2+ (aq) + Sn (s) → Sn2+ (aq) + Pb (s) is spontaneous because lead is lower than tin in the series
- Mg2+ (aq) + Ag (s) → Ag+ (aq) + Mg (s) is not spontaneous because magnesium is above silver in the series.
Lean more: https://brainly.com/question/24556237
