Answer
Please see the work below.
Work Step by Step
The reaction can be shown as:
${H_2}_{(g)}+{Cl_2}_{(g)}\rightarrow {2HCl}_{(g)}$
We know that:
$PV=nRT$
We plug in the known values to obtain:
$(101000)(0.0056)=n(8.31)(273)$
$n=0.249 \space moles$
As the mole ratio of $H_2:HCl=1:2$
The moles of $HCl=0.249\times 2=0.5 \space moles$
Finally, the mass of $HCl=moles \times molar mass=0.5\times 36.5=18.2g$
