Roles of Catalysts and Intermediates

Stephen Shabbat explains the differences between catalysts and reaction intermediates. Catalysts are consumed and regenerated, while intermediates are generated and consumed. Two examples are discussed: the decomposition of H2O2 and a reaction involving NO and N2O. In the H2O2 example, I- acts as a catalyst and IO- as an intermediate. In the NO and N2O reaction, NO is both a catalyst and a product, while NO2 is an intermediate and a reactant.

What is the primary role of a catalyst in a chemical reaction?

• To appear in the net stoichiometry

• To act as a reactant

• To be consumed and not regenerated

• To speed up the reaction without being consumed

Which of the following is true about reaction intermediates?

• They appear in the net stoichiometry

• They are generated and consumed during the reaction

• They are regenerated at the end of the reaction

• They act as catalysts

In the decomposition of H2O2, what role does I- play?

• Reactant

• Reaction Intermediate

• Product

• Catalyst

What is the role of IO- in the decomposition of H2O2?

• Catalyst

• Product

• Reactant

• Reaction Intermediate

What is the net reaction for the decomposition of H2O2?

• 2 H2O2 → 2 H2O + O2

• H2O2 + I- → H2O + IO-

• H2O2 + IO- → H2O + I-

• H2O2 → H2O + O2

In the reaction involving NO and N2O, what is the role of NO?

• Reaction Intermediate

• Catalyst

• Product

• Reactant

What is the role of NO2 in the reaction involving NO and N2O?

• Reaction Intermediate

• Catalyst

• Product

• Reactant

Which of the following statements is true about NO in the second example?

• NO is only a reactant

• NO is only a product

• NO is both a catalyst and a product

• NO is neither a catalyst nor a product

In the second example, what is the relationship between NO2 and the reactants?

• NO2 is both a reaction intermediate and a reactant

• NO2 is only a product

• NO2 is neither a reaction intermediate nor a reactant

• NO2 is only a reactant

What can be concluded about the roles of NO and NO2 in the second example?

• NO is a product and NO2 is a catalyst

• NO is a reactant and NO2 is a catalyst

• NO is a catalyst and NO2 is a reactant

• NO is a reactant and NO2 is a product