Very large equilibrium constant means its product dominant
reaction or reaction goes to completion .
After connection , Total volume = 3.8 + 3.6 = 7.4 litres.
Moles of Hydrogen = 3.8 x 0.0054 = 0.02052 moles
  Moles of F2  = 3.6 x 0.036 = 0.1296
moles
New molarity after connecting ,
[H2]Â Â Â Â = 0.02052/7.4 = 0.00277
MÂ Â Â limiting Reagent
[F2]Â Â Â Â = 0.1296/7.4 = 0.0175 M
  H2(g)   Â
+Â Â Â Â Â Â Â Â Â Â Â Â Â Â
F2(g)Â Â Â Â Â Â
↔        Â
2HF(g)Â Â
       Â
0.00277Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â
0.0175Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â
0
     (0.00277-0.00277 )
         (0.0175 -
0.00277)Â Â Â Â Â Â Â Â Â Â Â
2 x 0.00277= 5.54 x 10-3 M
          Â
