The E°(M2+/M) value for copper is positive (+0.34V). What is a possible reason for this? (Hint: consider its high ΔaH° and low ΔhydH°)
The E0(M2+/M) value of a metal depends on the energy changes involved in the following reactions:
1. Sublimation energy: The energy needed to convert one mole of atoms from a solid state to gaseous state.
2. Ionization energy: The energy supplied to remove electrons from one mole of atoms, which are in the gaseous state.
3. Hydration energy: The energy emitted to hydrate one mole of ions.
Now, copper has a high ionisation energy and low hydration energy. Hence, the E0(M2+/M) value for copper is positive.