Transition metals and their compounds show catalytic properties because

Options

A. They have comparatively small size
B. The can adopt multiple oxidation states and can from complexes
C. They have high ionisation enthalpy
D. They are coloured

Answer

**Solution:**

Transition metals and their compounds exhibit catalytic properties due to two main reasons:

1. **Variable Oxidation States**: Transition metals are characterized by their ability to exist in multiple oxidation states. This property allows them to form intermediate complexes during chemical reactions. When a transition metal reacts, it can change its oxidation state, which facilitates the formation of these intermediates. These intermediates can provide a new pathway for the reaction to occur, effectively lowering the activation energy required for the reaction to proceed.

2. **Availability of Empty d-Orbitals**: Transition metals have empty d-orbitals that can be utilized during reactions. These empty d-orbitals provide a larger surface area for reactants to interact with the catalyst. The presence of these d-orbitals allows the transition metals to absorb and re-emit a wide range of energies, which is crucial for providing the necessary activation energy for the reaction. This ability to interact with reactants and facilitate their transformation is what makes transition metals effective catalysts.

In summary, the catalytic properties of transition metals and their compounds arise from their ability to adopt variable oxidation states and the availability of empty d-orbitals, which together enable the formation of intermediate complexes and provide a favorable environment for chemical reactions.

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