Ozonolysis of propyne gives

The reaction is,

${\mathrm{CH}}_3\mathrm{C}=\mathrm{CH}\stackrel{{\mathrm{O}}_3}{⟶}{\mathrm{CH}}_3\mathrm{COOH}+\mathrm{HCOOH}$

Thus, Ozonolysis of propyne gives acetic and formic acids.