Xg of a pure sample of iron (II) sulphide reacted completely with excess dilute hydrochloric acid to give 3.20g of iron (II) chloride according to the following equation: FeS(_{(s)}) + 2HCI(_{(aq)}) –> FeCl(_{2(aq)}) + H(_2)S(_{(g)}).
(a) Mention one method apart from heating by which the reaction can be made to proceed faster
(b) Calculate the value of X. [CI = 35.5, Fe = 56; FeS = 88g mol(^{-1})]
Explanation
(a) Other means of increasing the rate of reaction of FeS + 2HCI (to) FeCl(_2) + H(_2)S apart from heating are:
– Use a more concentrated or increasing the concentration of the acid
– Grinding the FeS to powder.
(b) Calculation of X. Molar mass of FeCl(_2) = (56 + 2 x 35.5) = 127g/mol. From the equation, 127g FeCl(_2) = 88g FeS
3.20g FeCl(_2) will be obtained from (frac{88}{127}) x 3.2g FeS
X (Evaluation) = 2.22g