Identify the chemical reactions that serve as valid, strictly defined examples of heterogeneous cata — Surface Chemistry Chemistry Question

💡 Solution & Explanation

Heterogeneous catalysis strictly requires the catalyst to be in a distinctly different physical phase from the reactants. In options A, B, and D, solid catalysts ($Pt$ or $Fe$) are used with gaseous reactants. Option C is an example of homogeneous catalysis, as both the reactants and the $HCl$ catalyst are in the identical aqueous liquid phase.