(a) Name one product of destructive distillation of coal that is (i) solid (ii) liquid; (iii) gas.
(b) (i) What is the major component of synthetic gas? (ii) Give one reason why synthetic gas is not a major source of air pollution.
(c) (i) Write a balanced chemical equation for the complete combustion of carbon. (ii) State two: I. physical; II. chemical properties of the product in (c)(i).
(d) (i) Name two allotropes of carbon that are I. crystalline, II. amorphous. (ii) State one use of each of the allotropes named in (d)(i).
(e) (i) By means of balanced chemical equations only, outline the process of manufacture of H\(_2\)SO\(_4\), by contact process.
(ii) State the function of H\(_2\)SO\(_4\) in each of the following reaction equations:
I. C\(_2\)H\(_5\)OH\(_{2(l)}\) \(\to\) C\(_2\)H\(_{4(g)}\);
II. Pb(NO\(_{3(g)}\) + H\(_2\)SO\(_{4(g)}\) —> PbSO\(_{4(s)}\) + 2HNO\(_{3(aq)}\)
Explanation
(a)(i) coke (ii) ammoniacal liquor/coal tar (iii) coal gas
(b) (i) methane (ii) because sulphur is removed in the gasification process/it does not contain sulphur or sulphur compounds.
(c)(i) C\(_{(S)}\) + O\(_{2(g)}\) --> CO\(_{2(g)}\)
(ii) I. is a gas at room temperature - it is a colourless gas - it is an odourless gas - it is denser than air - it readily liquefies and solidifies/easily compressible.
II. - reacts with alkali to form trioxocarbonate (IV) - it is soluble in water - reacts with (burning) Mg to form MgO - reacts with red hot carbon to form CO - It is weakly acidic in water - it does not support combustion.
(d)(i) I. diamond graphite II. -coal/ lampblack/soot/carbon black - coke - charcoal.
(ii) I. Diamond - as a cutting tool - as jewellery;
Graphite - as a lubricant - as an electrode - as pigment in paints - as neutron moderators in nuclear reactors.
II. Coke - as a fuel -as a reducing agent/in the extraction of metals - preparation of carbides - for making water gas/producer gas.
Coal - as a fuel -as a starting material for chemicals.
Charcoal - as a fuel - as absorbent/in gas mask - in the purification of gases - in the recovery of industrial solvent - for removing colouring matter from substances
Lampblack/Soot/carbon black: - to colour rubber tyres - to make boot/shoe polish - to make printers ink - to make black paint - typewriting ribbons - carbon paper.
(e)(i) I. S\(_{(s)}\) + O\(_{2(g)}\) --> SO\(_{2(g)}\)
II. 2SO\(_{2(g)}\) + O\(_{2(g)}\) \(\rightleftharpoons\) 2SO\(_{3(g)}\)
III. SO\(_{3(g)}\) + H\(_2\)SO\(_{4(g)}\) -> H\(_2\)S\(_2\)O7\(_{7(l)}\)
IV. H\(_2\)SO7\(_{7(l)}\) + H\(_2\)O\(_{(l)}\) -> 2H\(_2\)SO\(_{4(l)}\)
(ii) I. - dehydrating agent
II. precipitating agent/displacement agent.