Question

Which reactions represents heterogeneous catalysis?

• A. Decomposition of KClO${}_3$ in presence of MnO${}_2$
• B. Ostwald process for HNO${}_3$
• C. Contact process for H${}_2$SO${}_4$
• D. Acidic hydrolysis of ester

Answer 1

Answer: (A), (B), (C)

The correct options are
A Decomposition of KClO${}_3$ in presence of MnO${}_2$
B Ostwald process for HNO${}_3$
C Contact process for H${}_2$SO${}_4$

Heterogeneous catalysis refers to the form of catalysis where the phase of the catalyst differs from that of the reactants. Phase here refers not only to solid, liquid or gas but also immiscible liquids.
All other given reactions are example of this but in acidic hydrolysis, reactant and catalyst ($H^{+}$) both are miscible liquids. So, it is homogeneous catalysis.