1.1. The structure of pentanal is shown below.

Draw the structure of a branched isomer of pentanal that exhibits optical isomerism.

1.2. Draw the structure of a branched isomer of pentanal that does not exhibit optical isomerism.

1.3. Some skeletal examples of unbranched aldehydes and unbranched ketones are shown below.

In terms of optical isomer products, compare the reactions of unbranched aldehydes and unbranched ketones with HCN.

1.4. One of the ketones, shown in part (c), will form an optical isomer when it reacts with HCN.

i) Identify the ketone that will form an optical isomer with HCN and name the product.

ii) Draw 3D representations of the two optical isomers produced.