Which reaction below will occur when Cd (s) and Zn (s) are added to a solution that contains both Cd2+ and Zn2+ ions?
Cd (s) + Zn2+ (aq) → Cd2+ (aq) + Zn (s)
Zn (s) + Cd2+ (aq) → Zn2+ (aq) + Cd (s)
Both of the above reactions occur.
Neither of the above reactions occur.
Here is a link to the activity series. A METAL will displace another metal ION below it in the activity series.
Therefore, Zn will displace Cd^2+ but not the other way around.
http://www.files.chem.vt.edu/RVGS/ACT/notes/activity_series.html
Zn(s) + Cd*2+(aq) ==> Cd(s) + Zn^2+(aq)
Both of the above reactions occur.
To determine which reaction will occur when Cd (s) and Zn (s) are added to a solution containing Cd2+ and Zn2+ ions, we need to consider the activity series of metals.
The activity series is a list of metals organized in order of decreasing reactivity. Metals higher in the activity series are more reactive and can displace metals lower in the series from their compounds in solution.
In this case, we have Cd (s) and Zn (s) being added to a solution containing Cd2+ and Zn2+ ions. Comparing the activity series, we find that Cd is below Zn. This means that Zn is more reactive than Cd.
According to the activity series, a metal can only displace a metal ion from its compound if it is higher in the series. Therefore, Zn (s) can displace Cd2+ from its compound, leading to the reaction:
Zn (s) + Cd2+ (aq) → Zn2+ (aq) + Cd (s)
On the other hand, Cd (s) cannot displace Zn2+ from its compound because Cd is below Zn in the activity series. Therefore, the reaction:
Cd (s) + Zn2+ (aq) → Cd2+ (aq) + Zn (s)
will not occur.
In conclusion, the correct answer is:
Zn (s) + Cd2+ (aq) → Zn2+ (aq) + Cd (s)