Which pair of reactants will not react?
Au(s) with Hg^2+ (aq)
Pt^2+ (aq) with Au(s)
Ag(s) with Cu(s)
Au(s) -> Au^3+(aq) + 3e-
Hg(s) -> Hg^2+(aq) + e-
Pt(s) -> Pt^2+(aq) + 2e-
Cu(s) -> Cu^2+(aq) + 2e-
My guess is all of them, but I am not entirely sure.
Here is an activity series table. Use it to answer the question.
http://www.grandinetti.org/activity-series
Here is how you do it.
Any METAL will displace (react with) any METAL ION below it in the activity series. For example,
Sn will react with Cu^2+ ion.
Sn + CuCl2 ==> SnCl2 + Cu because the free element Sn is above Cu in the activity series but
Cu + SnCl2 ==> no reaction because Cu is BELOW Sn in the activity series.
To determine which pair of reactants will not react, we need to compare the reduction potentials of the reactants. If the reduction potential of one reactant is greater than the other, a reaction will occur. If the reduction potential of both reactants is the same, no reaction will occur.
Let's compare the reduction potentials for each pair of reactants:
1. Au(s) with Hg^2+(aq)
The reduction potential of Au^3+(aq) is +1.498 V, while the reduction potential of Hg^2+(aq) is +0.851 V. Since the reduction potential of Au^3+(aq) is greater than Hg^2+(aq), Au(s) will react with Hg^2+(aq).
2. Pt^2+(aq) with Au(s)
The reduction potential of Pt^2+(aq) is +1.20 V, which is lower than the reduction potential of Au^3+(aq) (+1.498 V). Therefore, no reaction will occur between Pt^2+(aq) and Au(s).
3. Ag(s) with Cu(s)
The reduction potential of Ag^+(aq) is +0.7996 V, while the reduction potential of Cu^2+(aq) is +0.337 V. Since the reduction potential of Ag^+(aq) is greater than Cu^2+(aq), Ag(s) will react with Cu(s).
Based on the comparison of reduction potentials, the pair of reactants that will not react is Pt^2+(aq) with Au(s).
To determine whether a pair of reactants will react or not, you need to compare the standard reduction potentials (E°) of each half-reaction involved. The reaction will occur if the reduction potential of the oxidizing agent (the species being reduced) is greater than that of the reducing agent (the species being oxidized).
Let's analyze each pair of reactants:
1. Au(s) with Hg^2+ (aq)
From the given half-reactions, we can determine the reduction potentials:
Au^3+(aq) + 3e- -> Au(s) E° = +1.50 V
Hg^2+(aq) + e- -> Hg(s) E° = +0.85 V
In this case, Au^3+ is a stronger oxidizing agent than Hg^2+. Since the reduction potential of Au^3+ is greater, the reaction will occur, and Au(s) will react with Hg^2+ (aq).
2. Pt^2+ (aq) with Au(s)
Again, comparing the reduction potentials:
Au(s) -> Au^3+(aq) + 3e- E° = +1.50 V
Pt^2+(aq) + 2e- -> Pt(s) E° = +1.20 V
Here, Au^3+ is still the stronger oxidizing agent. Thus, the reaction will occur, and Au(s) will react with Pt^2+(aq).
3. Ag(s) with Cu(s)
Comparing the reduction potentials:
Ag(s) -> Ag^+(aq) + e- E° = +0.80 V
Cu(s) -> Cu^2+(aq) + 2e- E° = +0.34 V
In this case, Cu^2+ is a stronger oxidizing agent than Ag^+, indicating that Ag(s) is a stronger reducing agent. Therefore, there will be no reaction between Ag(s) and Cu(s) since the reduction potential of Cu^2+ is lower than that of Ag(s).
To summarize:
- Au(s) will react with Hg^2+ (aq).
- Au(s) will react with Pt^2+(aq).
- Ag(s) will not react with Cu(s).