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Optical isomers

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Why bother with a post grad course - waste of time? 17-10-2016
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    Can someone explain how to get the 3 marks for 4b.

    The mark scheme isn't very clear.
    How do you know product Q is a racemic mixture?

    The question tells you that you cannot distinguish between the two by testing optical activity. We know that R doesn't form an optically active compound so it will show no optical activity. Therefore Q, which does form a compound with a chiral centre, must form an equal mixture of enantiomers and won't rotate polarised light.

    I'm not too sure why it forms a racemic mixture but I think it might be because the C double bond O is planar so there is an equal likelihood of attack from either side therefore forming a racemic mixture.
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