Question

(a) Write the balanced equations for the preparation of the following compounds (as the major product), starting from iron and using only one other substance:
(i) iron (II) chloride
(ii) iron (III) chloride
(iii) iron (II) sulphate
(iv) iron (II) sulphide
(b) Write the equations for the laboratory preparation of
(i) sodium sulphate using dilute sulphuric acid.
(ii) lead sulphate using dilute sulphuric acid.

Answer 1

(a) (i) Iron reacts with dilute hydrochloric acid to form iron (II) chloride.

Fe + 2HCl → FeCl₂ + H₂

(ii) When dried chlorine gas is passed over heated iron, it forms anhydrous iron (III) chloride.

2 Fe + 3 Cl₂ → 2 FeCl₃

(iii) Iron (II) sulphate is prepared in the displacement reaction that takes place between iron metal and dilute sulphuric acid.

Fe + H₂SO₄ → FeSO₄ + H₂

(iv) Iron (II) sulphide is prepared by the synthesis method in which elements present in the compound react directly with heat.

$\mathrm{Fe}+\mathrm{S}\stackrel{\mathrm{heat}}{\to }\mathrm{FeS}$

(b) (i) Sodium sulphate is prepared by the neutralisation of sodium hydroxide base with dilute sulphuric acid.

$2\mathrm{NaOH}+{\mathrm{H}}_2{\mathrm{SO}}_4\stackrel{∆}{\to }{\mathrm{Na}}_2{\mathrm{SO}}_4+2{\mathrm{H}}_2\mathrm{O}$

(ii) Lead sulphate is prepared by treating lead nitrate with dilute sulphuric acid.

$\mathrm{Pb}({\mathrm{NO}}_3{)}_2+{\mathrm{H}}_2{\mathrm{SO}}_4\to {\mathrm{PbSO}}_4+2{\mathrm{HNO}}_3$