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    if it is racemic, it doesn't rotate the plane

    i'm confused as the mark scheme says that for an optical isomer it doesn't rotate it cos it is 50:50 but i thought optical isomers do rotate the plane?
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    (Original post by the_wizzz)
    if it is racemic, it doesn't rotate the plane

    i'm confused as the mark scheme says that for an optical isomer it doesn't rotate it cos it is 50:50 but i thought optical isomers do rotate the plane?
    Yup. PURE optical isomer do give a rotation.
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    they cancel each other out
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    the racemic mixture has both isomers in equal amounts so rotates both ways but cancels it out so no rotation
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    a racemic mixture has equal concentrations of both optical isomers (laevorotary and dextrorotary)...each will rotate the plane clockwise or anticlockwise...yet as they are both in the same conc the rotation is cancelled out.
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    As 50% are rotating the plane of polarisation clockwise, and 50% are rotating the plane of polarisation anticlockwise, the over net affect is 0, i.e. there is no movement in either direction. The mixture is racemic
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    oh, so when the optical isomer is by itself, it can rotate the plane?
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    yep it duz
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    thanks!
 
 
 
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