Answer
$C_2H_2Cl_2$
Work Step by Step
$\text{ Molar Mass}=\frac{\frac{0.800}{0.256}*0.08206*373}{\frac{750}{760}}=96.9\text{ g/mol}$
$\text{ Molar Mass of } CHCl=48.4689$
$\frac{96.9}{48.4689}=2$
Therefore, the molecular formula is $C_2H_2Cl_2$