Catalysts speed up reversible reactions without shifting equilibrium

Steps:

• Catalysts lower activation energy for both forward and reverse reactions equally, increasing rate but not changing equilibrium position.
• Iron is a known catalyst for hydrogen reactions, such as in hydrogenation or ammonia synthesis.
• Aluminum does not typically catalyze reactions involving solids and hydrogen due to its protective oxide layer.
• Thus, only iron catalyzes the reaction, with no effect on equilibrium position.

Why D is correct:

• Catalysts do not alter the equilibrium constant (K), as they affect rates equally; this follows from the definition that equilibrium position depends on K, unchanged by catalysts.

Why the others are wrong:

• A: Aluminum does not catalyze, and no catalyst shifts equilibrium right.
• B: Iron does catalyze, so not both have no effect.
• C: Only iron catalyzes, not both, and equilibrium does not move right.

Final answer: D