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