(a) What term is used to describe each of the following processes?
(i) Alkaline hydrolysis of fats and oils;
(ii) The conversion of glucose into ethanol by enzymatic action;
(iii) Thermal decomposition of higher petroleum fractions into lower molecular mass hydrocarbons in the presence of catalyst.
(b)(i) Write the structure and IUPAC name for one alkanoic acid with the molecular formula C(_4)H(_8)0(_2).
(ii) Arrange the following compounds in order of increasing boiling point: Butane; Butanoic acid; Methylpropane.
(iii) Give an explanation for your answer in (b)(ii).
(c)(i) Ethanol was used for preparing a gas X which decolorized bromine water. Identify X and describe briefly its laboratory preparation.
(ii) Write an equation to show how ethanol reacts with sodium
(iii) Give the reagent and reaction conditions for the conversion of ethanol into C(_2)H(_5)COOC(_2)H(_5).
(d) State the type of recction involved in each of the conversions indicated below:
(i)C(_6)H(_6)C(_6)H(_5)CH(_3)
(ii) nC(_2)H(_4) (to) (CH(_2) – CH(_2)),
(iii) CH(_3)CH(_2)CH(OH)CH(_3) -> CH(_3)CH(_2)CCH(_3)
(iv) (C(_6)H(_{10})O(_5)) -> C(_6)H(_{12})O(_6).
(iv)
Explanation
(a) Saponification
(ii) Fermentation
(iii) Catalytical cracking/thermal cracking
(b)(I) C(_4)H(_8)O(_2) ; CH(_3)CH(_2)CH(_2)COOH(1 – butanoic acid) OR CHCH(CH(_3))COOH (2 methyl – 1 – propanoic acid.)
(ii) Butanoic acid > Butane > methyipropane
(iii) Butanoic acid is a liquid and heavier than butane. butane though a gas is heavier and more stable than methyipropane.
(c)(i) The gas is ethene. Ethene is prepared in the laboratory by action of ethanol on concentrated H(_2)SO(_4). The overall reaction is a catalytic dehydration of ethanol. C(_2)H(_5)OH (to) C(_2)H(_4)
(ii) -H(_2)O
2C(_2)H(_5)OH + 2Na (to) 2C(_2)H(_5)ONa + H(_2).
Conc. H(_2)SO(_4)
(iii) The reagents are ethanol (C(_2)H(_5)OH) and propanoic acid (C(_2)H(_5)COOH). The reaction conditions are (i) Temperature of 150°C and concentrated H(_2)SO(_4).
(d)(i) Substitution reaction
(ii) Polymerisation reaction
(iii) Catalytic dehydration
(iv) Hydrolysis
(v) Addition reaction.