The hydrolysis of ${\mathrm{CH}}_3{\mathrm{CH}}_2{\mathrm{NO}}_2$  with 85% ${\mathrm{H}}_2{\mathrm{SO}}_4$gives

The reaction is,

${\mathrm{CH}}_3{\mathrm{CH}}_2{\mathrm{NO}}_2+{\mathrm{H}}_2\stackrel{{\mathrm{H}}_2{\mathrm{SO}}_4}{⟶}{\mathrm{CH}}_3\mathrm{COOH}+{\mathrm{NH}}_2\mathrm{OH}$.

Thus, The hydrolysis of ${\mathrm{CH}}_3{\mathrm{CH}}_2{\mathrm{NO}}_2$  with 85% ${\mathrm{H}}_2{\mathrm{SO}}_4$gives ${\mathrm{CH}}_3\mathrm{COOH}$.