For a chemical reaction can never be a fractional number.

For a chemical reaction, molecularity is never be a fractional number.

$\mathrm{Ex}:{\mathrm{CH}}_3\mathrm{COOH}+{\mathrm{CH}}_3\mathrm{OH}\to {\mathrm{CH}}_3{\mathrm{COOCH}}_3+{\mathrm{H}}_2\mathrm{O}$

The number of reactant molecules participate in the given reaction is 2.

$\therefore$Which is a bimolecular reaction.