Suppose a sample of an initially pure single enantiomers of tartaric acid [@]D=+12.4°(H2O) underwent a chemical isomerization reaction which yielded 10% of the other enantiomers and 20% meso isomer in addition to 70% of the starting compound.
Q1 What is enantiomeric excess of the major enantiomers in the final solution?
Q2 If 1 g of the total mixture(including meso)was dissolved in 1mL of water and teh optical-rotation measured in a 1dm cell,what would be the observed rotation of teh solution?
Q3 From the total mixture,chromatographic separation on silica gel(a coomonly used achiral adsorbent) might be expected to yield one of three components in pure state.WHich one????
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2 Answers
1357as 10% is the other enantiomer, 20% of the mixture will be racemic (10& from major)
enantiomer excess=70-10=60%
1357specific rotation of mixture=0.6*12.4°=7.44°
[a]=a/cl
observed rotation a=[a]cl=7.44° g ml-1 dm
