write a balanced equation for this reaction. find out the mass of hydrogen chloride gas needed to react completely with 0.20 g of ammonia gas.

Answer 1

First write the balanced reactuion.

THEN compute how much HCl is needed.

The balanced reaction is

HCl + NH3 -> NH4Cl

The molar mass of NH3 is 17 g.
0.20 g of NH3 is 0.01177 moles.

You need an equal number of moles of HCl. Convert that to mass.