Isomerism: Structural Isomerism & Stereoisomerism (CIE A Level Chemistry)

A chemist is analysing a collection of organic compounds.

Some of these compounds are shown in Table 1.1.

Compound	IUPAC name	Displayed formula	Skeletal formula
1	Z-2-chloro-but-2-en-1-ol
2	2-chloropropanal
3
4

  

Complete Table 1.1.

State the empirical formula of compound 1.

Explain why compound 1 exists as two stereoisomers, but compound 4 does not.

Compounds 2 and 3 both exhibit the same type of isomerism.

There are many different chemicals with the same molecular formulae but different arrangements of atoms in three-dimensional space. 

C₄H₈ exists as several isomers.

Draw the displayed formulae of the following compounds and, where appropriate, identify any chiral centres. 

• 2,4-dimethylhexan-3-ol
• 2,4-dimethyl-3-chloropentane
• 2-aminobutane

1-bromopropan-1-ol exhibits optical isomerism.

Draw 3D representations of the two enantiomers of 1-bromopropan-1-ol.

Butan-2-ol is used as a solvent, in industrial cleaners, in paint removers and in the manufacture of other chemicals such as butanone.

Draw the fully displayed formula of butan-2-ol and the positional isomer of butan-2-ol.

Name the branch chain isomers of butan-2-ol.

Explain why butan-2-ol does not exhibit stereoisomerism.

The organic compounds in Fig 1.1 are all made by living organisms.

Fig. 1.1

Compounds B, C, D and E all show the same type of isomerism.

Circle the functional group(s) responsible for this isomerism on the molecules in Fig 1.1.

Compound D reacts with hydrogen chloride to form two products.

Name the type of reaction occurring when compound E reacts to form methanol and deca-2,4-dienoic acid.