Question

Give reasons for the following:

Many of the transition metals and their compounds act as catalysts.

Answer 1

1. Presence of vacant d-orbitals that can accommodate electrons.
2. Ability to exhibit variable oxidation states (variable valencies), which helps in forming unstable reaction intermediates.
3. Tendency to form complexes, stabilizing intermediate species.
4. Finely divided metals provide a large surface area with free valencies, helping reactant molecules adsorb and come closer.
5. These unstable intermediates lower the activation energy, increasing the reaction rate. The catalyst is then regenerated.