What mass of chlorine gas is necessary to synthesize 174 liters of hydrogen chloride at stp?

  The  mass  of  chlorine  gas    is  calculated   as  follows

find  the  moles   HCl  ,  At  STP  1moles  = 22.4  liters
  what  about  174 L
 moles =  174l  x  1mole/22.4L= 7.77 moles
write the  equation   for    reaction

H2 +  Cl2 =2HCl
 by  
use  of mole  ratio  between cl2  to   HCl (1:2)  the  moles   of  Cl2 =7.77/2  =  3.885  moles

mass is  therefore  =  3.885 mol  x  71 gmol  =  275.84 grams

It's either 3 or that ,,but if not than choose 4

You need to divided twenty four by a dozen them by the temperature it is getting cook by