Chemistry, Third edition

348 18 · COMMON CLASSES OF ORGANIC COMPOUNDS

Revision questions

18.1.Write the structural formulae of the following:

(i) hexan-2-ol

(ii)2-methylpropan-2-ol

(iii)butane-1,3-diol

(iv)3-chlorophenol.

18.2.Arrange in order of increasingacidity:

ethanoic acid, ethanol, phenol, water.

18.3.Write the structural formulae for

(i) 3-methylhexanal

(ii)pentane-2,4-dione

(iii)phenylethanone

(iv)2-methylpropanoic acid

(v)butane-1,4-dioic acid.

18.4.What would be the likely product of the oxidation of
ethane-1,2-diol with excess acidified dichromate?

18.5.Write the structures of the organic products of the fol-
lowing reactions:

(i) The reaction when propanoic acid is heated with ethanol

in the presence of concentrated sulfuric acid.

(ii)The reduction of propanoic acid with lithium aluminium

hydride.

(iii)The oxidation of pentanal with sodium dichromate.

(iv)The oxidation of ethanal with Fehling’s solution.

18.6.Write the structural formula of the following derivatives

of methanoic acid:

(i) the propyl ester

(ii)the amide

(iii)the acid chloride.

18.7.The compound 2-amino-3-hydroxypropanoic acid is

more commonly known as serine and is an amino acid:

(i) Write the structural formula of serine.

(ii)Does serine exist as two different optical isomers?

(iii)What would be the structure of the product formed

when serine is treated with acidified sodium dichromate

solution?

(iv)Write the structural formula of the dipeptide Ser-Ser.

18.8.Write an equation for the acid-catalysed reaction of

methanol with benzoic acid.

18.9.Write the structural formula of a fat derived from the

esterification reaction of one molecule of glycerol and three

molecules of octadecanoic acid (‘octadec’ = 18).

18.10.Identify the functional groups in the following well-

known compounds:

(i) the synthetic fibre Dacron

(ii)amphetamine

(iii)aspirin

(iv)urea

BOX 18.6

Examples of reactions of ethanol, phenol and benzyl alcohol

Phenol Ethanol Benzyl alcohol

No ester formed when ester formed ester formed

reacted with an organic

acid

No simple product aldehyde/acid aldehyde/acid

formed on oxidation formed on oxidation formed on oxidation

Reacts with neutral FeCl 3 no colour produced no colour produced

to give a violet complex with the same reagent with the same reagent