Question

It is true that

<!--td {border: 1px solid #ccc;}br {mso-data-placement:same-cell;}--> JEE MAINS 2020

Answer 1

Zero order reaction has complex mechanism. Zero order reaction is a multistep reaction
For elementary or single step reactions the order and molecularity of the reaction are same.
Now assume that zero order reactions are elementary or single step reaction ,then its molecularity=0.
But since zero order reactions exists therefore its molecularity can never be zero{A zero molecularity implies that no effective collisions between reactant molecules takes place i.e reaction does not occurs at all}.This implies that molecularity for the overall zero order reaction is not defined or doesn't exists.Thus a zero order reaction must be multi step/complex reaction such that the individual steps have their own molecularity but molecularity for the overall reaction is not defined as seen in multi step/complex reaction..