Which metal ion is reduced by lead?Group of answer choicespotassiumcalciummercurycadmium

To determine which metal ion is reduced by lead, we first need to consider the standard reduction potentials of the metal ions listed:

1. Potassium (K⁺) - Potassium has a very negative standard reduction potential, indicating that it is highly reactive and is not easily reduced.
2. Calcium (Ca²⁺) - Similar to potassium, calcium also has a very negative reduction potential and is unlikely to be reduced.
3. Mercury (Hg²⁺) - Mercury has a more favorable standard reduction potential compared to potassium and calcium, making it more likely to be reduced.
4. Cadmium (Cd²⁺) - Cadmium also has a favorable reduction potential, but we need to compare it directly with mercury.

When evaluating the ability of lead (Pb) to reduce these ions, we need to remember that a metal will reduce another metal ion if it has a higher (more positive) standard reduction potential than the ion being reduced.

Based on standard reduction potential values, lead can effectively reduce mercury ions. Consequently, the metal ion that is reduced by lead is mercury (Hg²⁺).

Final Answer

The metal ion that is reduced by lead is mercury (Hg²⁺).