Suggest a reasonable explanation for each of the following observations:
(a) The second-order rate constant k for saponification of ethyl trifluoroacetate is over 1 million times greater than that for ethyl acetate (25°C).
(b) The second-order rate constant for saponification of ethyl 2, 2-dimethylpropanoate, (CH3)3CCO2CH2CH3, is almost 100 times smaller than that for ethyl acetate (30°C).
(c) The second-order rate constant k for saponification of methyl acetate is 100 times greater than that for tert-butyl acetate (25°C).
(d) The second-order rate constant k for saponification of methyl m-nitrobenzoate is 40 times greater than that for methyl benzoate (25°C).
(e) The second-order rate constant k for saponification of 5-pentanolide is over 20 times greater than that for 4-butanolide (25°C).