(a) Describe briefly a suitable procedure for preparing a pure sample of MgSO\(_4\) starting from MgO.

 

(b)(i) Mention two sources of water pollution.

(ii) Explain why the sample of air collected in the process of boiling water is richer in oxygen than atmospheric air

(iii) Mention one substance used as coagulant in water treatment plants.

 

(c)(i) State two physical porperties of chlorine.

(ii) Write an equation to show how chlorine reacts with iron

(iii) Why is Chlorine preferred to sulphur (IV) oxide in the bleaching of cotton

 

(d) Bleaching powder reacts with dilute HCl according to the reaction below;

CaOCl\(_{2(s)}\) + 2HCI\(_{(aq)}\) -> CaCl\(_{2(aq)}\) + H\(_2\)O\(_{(l)}\) + Cl\(_{2(g)}\)

Calculate the mass of bleaching powder that will produce 400cm\(^3\) of chlorine at 25\(^o\)C and a pressure of 1.20 x 10\(^5\) NM\(^{-2}\). [O = 16.0; Cl = 35.5; Ca = 40.0;1 mole of gas occupies 22.4 dm\(^3\) at s.t.p; standard pressure = 1.01 x 10\(^6\) Nm\(^{-2}\)]