The process of racemization of an optically compound is entropy driven and hence nature prefers a racemic mixture to an optically active one, which is consistent with the idea of the intuitive understanding of entropy as the degree of randomness or disorder. Then, how can the entropy change of a process of conversion of an optically pure compound to its racemic mixture be computed theoretically or atleast estimated accurately enough so that it can be compared for two different reaction outcomes or the spontaneity of a reaction be estimated?

Moreover, which has higher entropy, a racemic mixture or a mixture of all possible stereoisomers of a compound including the meso form? In the later case, there is more randomness and hence should possess greater entropy. Can we treat a mixture of stereoisomers as a mixture of two different compounds and then use their mole fractions (or activities) to calculate the entropy of mixing which in case of gases is $-nR(x_1\ln {x_1} +x_2\ln{x_2})$.

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    $\begingroup$ There is really no way to address this question based upon the completely untrue idea that entropy is the same thing as randomness. Entropy is the distribution of states available. You need to quantify whether or not a change in entropy increases or decreases the number of states available. $\endgroup$
    – Lighthart
    Jun 11, 2014 at 22:41


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