Edexcel IAL Chemistry 15.2 Optical isomerism and chiral centres

Check whether one carbon is bonded to four different groups, then use wedge and dashed bonds or mirror-image drawings to show the stereochemical relationship.

Exam points

Mark or count chiral centres in displayed, skeletal, amino acid or medicine structures.
Explain optical isomerism through non-superimposable mirror-image enantiomers.
Draw 3D enantiomer diagrams with wedges, dashed bonds and a true mirror relationship.

[Maximum number: 1]

This question is about carboxylic acids and their derivatives.

Lactic acid, $\mathrm{CH}_{3} \mathrm{CH}(\mathrm{OH}) \mathrm{COOH}$ , is produced in muscles as a result of anaerobic respiration.

The structure of lactic acid is

Figure for Question 15.2—Optical isomerism results from chiral centre(s) in a molecule with asymmetric carbon atom(s) and that optical isomers question 1 — Edexcel A-Level Chemistry A2

Give a reason why lactic acid shows optical isomerism.
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15.2—Optical isomerism results from chiral centre(s) in a molecule with asymmetric carbon atom(s) and that optical isomers question 1