Catalysts classified by phase relative to reactants

Steps:

• Reaction 1 involves gaseous reactants (N2, H2) and solid Fe catalyst, differing in phase.
• This makes reaction 1's catalyst heterogeneous, as it is in a different phase from reactants.
• Reaction 2 uses vaporized (gaseous) tetrachloroethane catalyst under UV light, implying gaseous reactants for photochemical process.
• Thus, reaction 2's catalyst is homogeneous, same phase as reactants.

Why C is correct:

• Heterogeneous catalysts are in a different phase (solid Fe vs. gases); homogeneous are in the same phase (gaseous catalyst vs. likely gaseous reactants), per standard catalyst definitions.

Why the others are wrong:

• A: Reaction 2 uses homogeneous catalyst, not heterogeneous.
• B: Reaction 1 uses heterogeneous catalyst, not homogeneous.
• D: Reverses the catalyst types for each reaction.

Final answer: C