Question

Thermal decomposition of $HI$ on gold surface is a

• A. 1st order reaction
• B. 2nd order reaction
• C. 3rd order reaction
• D. zero order reaction.

Answer 1

Answer: (D)

zero order reaction.

Answer 2

Thermal decomposition of HI on gold surface, is an example of zero order reaction as the concentration of the gaseous reactant on the metal surface remains constant. This is because, as the reactants react off on the surface, more molecules are adsorbed on the surface and rate remains constant throughout.