Organic chemical reaction rate

The order of hydrolysis reaction speed is: a > d > b > C.

Hydrolysis is a nucleophilic substitution reaction, and the speed of nucleophilic substitution reaction depends on the positive charge and the steric hindrance of the central carbon atom. The stronger the positive charge, the faster the steric hindrance. In the above molecular structure, nitro group is an electron-withdrawing group, which will make the positive charge of the central carbon atom more prominent and prone to hydrolysis reaction. Methoxy is an electron-pushing group, which will reduce the positive charge of the central carbon atom and slow down the hydrolysis reaction rate. The charges of other molecules are between the two, so the above results are obtained.