Question

Iron (II) sulfide reacts with hydrochloric acid according to the reaction: FeS(s) + 2 HCl(aq)→ FeCl2(s) + H2S(g) A reaction mixture initially contains 0.223 mol FeS and 0.652 mol HCl. Once the reaction has occurred as completely as possible, what amount (in moles) of the excess reactant is left?

Answer 1

The amount ( in moles  of excess  reactant that is left is 0.206 moles

Explanation

FeS(s)  + 2HCl  (aq) →  FeCl2 (s)  + H2S (g)

• by use of mole ratio of FeS: HCl which is  1:2 this means that  0.223 mole  of FeS  reacted  completely with 0.223   x   2/1 =0.446  moles  0f FeCl2.

• HCl was in  excess because  0.446 moles of HCl reacted and initially  there was  0.652  moles.

• Therefore the  amount that was left

      = 0.652- 0.446  =0.206  moles