Question 1

How does a catalyst increase reaction rate?

Accepted Answer

A catalyst provides an alternative reaction pathway with a lower activation energy. More reacting molecules can therefore cross the activation barrier at the same temperature, so the reaction rate increases.

Question 2

Why is a catalyst unchanged in the overall reaction?

Accepted Answer

A catalyst may participate in intermediate steps, but it is regenerated at the end of the catalytic cycle. Thus it does not appear as a reactant or product in the overall reaction and is not chemically consumed.

Question 3

Does a catalyst shift the equilibrium position?

Accepted Answer

No. A catalyst does not change the equilibrium constant, the equilibrium composition or the overall thermodynamic ΔG. It only helps the system reach equilibrium more quickly.

Question 4

Why are many d-block elements useful as catalysts?

Accepted Answer

Transition elements can adopt multiple oxidation states and form complexes with different ligands. These properties allow suitable species and intermediates to form during catalytic cycles.

Question 5

Which catalysts are linked to the contact process, Haber process and catalytic converters?

Accepted Answer

V2O5 is used in the contact process, iron is used in the Haber process, and Pt, Pd and Rh are used in catalytic converters. The catalyst and industrial process must be matched correctly.

Catalyst Surface: Lower Activation Energy, Same Equilibrium

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