Reactions between uncharged polar molecules

Typical observed values for A are 102-107 mol-1 dm3 s-1, and there is a large variation for a given reaction in different solvents. 

Since the reactants are molecules, the extent of solvation will be small and approximately the same for all solvents. But the extent of charge separation in the activated complex is very dependent on the solvent, by virtue of the magnitude of the relative permittivity, and a large variation in the extent of solvation of the activated complex is expected. The entropy of activation and the A factor are expected to vary with change of solvent. 

Question. Assuming that the reaction step is associative, interpret the signs and magnitudes of the A values for the following reactions in terms of charge and complexity of structure  

Reaction AX2 Type of reaction Effect of charge Effect of complexity Effect of solvation Comments 

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