(a) State the role of each of the following substances in the treatment of river water for town supply (i) Sand bed. (ii) Alum (iii) Chlorine

 

(b)(i) Give three major uses of H\(_2\)SO\(_4\)

(ii) Explain the following observation: A strip of blue litmus paper dropped into concentrated H\(_2\)SO\(_4\) becomes charred whereas in dilute H\(_2\)SO\(_4\), it turns red and is not charred.

(iii) Write an equation to show how concentrated H\(_2\)SO\(_4\) reacts with zinc.

 

(c)(i) List two gaseous pollutants that can be generated by burning coal.

(ii) Explain why coal burns more easily when it is broken into pieces than when it is in lump form.

(ii) What gas is responsible for most of the explosions in coal mines?

(iv) Name: the non-volatile residue left behind after the destructive distlillation of coal

 

(d)(i) What is meant by allotropy?

(ii) Name two crystalline allotropes of carbon

(iii) Name two elements apart from carbon, which exhibit allotropy

(iv) It is now known that carbon has an allotropic form called fullerene, containing molecules of formula C\(_{60}\). Calculate the mass of one mole of these molecules [C = 12]