Question

Given the following list from the activity se- ries of metals (from most active to least ac- tive) K, Na, Al, Mn, Cr, Cd, Co, Pb, Hg which reaction would you NOT expect to occur?

1. Na(s) + Mn2+(aq) → Na+(aq) + Mn(s)
2. Co2+(aq) + Al(s) → Al3+(aq) + Co(s)
3. Cd(s) + Pb2+(aq) → Pb(s) + Cd2+(aq)
4. Al3+(aq) + Cr(s) → Cr3+(aq) + Al(s)
5. All of the listed reactions will occur.

Answer 1

Step-by-step explanation:

According to the activity series of metals, the reaction that would not be expected to occur is:

Al3+(aq) + Cr(s) → Cr3+(aq) + Al(s)

This is because aluminum (Al) is higher on the activity series and is less likely to be oxidized (lose electrons), while chromium (Cr) is lower on the activity series and is more likely to be oxidized. In this reaction, aluminum would have to be oxidized, which is not consistent with its position on the activity series.

All of the other reactions listed are expected to occur because they involve the transfer of electrons from a metal that is lower on the activity series to a metal that is higher on the series.