Rate of the Reaction:
The rate of a chemical reaction is defined as the change in concentration of a reactant or product per unit time. In this case, the rate of the reaction CH3COOC2H5 + NaOH → CH3COONa + C2H5OH can be expressed as rate = k [CH3COONa][NaOH], where k is the rate constant.

Effect of Adding Water:
When water is added to the reaction mixture, it will increase the total volume of the solution. This will result in a decrease in the concentration of both CH3COONa and NaOH. However, the ratio of their concentrations ([CH3COONa]/[NaOH]) will remain constant, as it is determined by the stoichiometry of the balanced chemical equation.

Explanation:
When three times water is added to the reaction mixture, the concentration of both CH3COONa and NaOH will decrease by a factor of 3. Let's assume the original rate of the reaction is R1.

Comparison of Rates:
The rate equation for the reaction, rate = k [CH3COONa] [NaOH], shows that the rate is directly proportional to the concentrations of both CH3COONa and NaOH. Therefore, when the concentrations of these reactants decrease by a factor of 3, the rate of the reaction will also decrease by the same factor.

The rate of the reaction after adding three times water can be expressed as R2 = k ([CH3COONa]/3) ([NaOH]/3). Simplifying this expression, we get R2 = (1/9) k [CH3COONa] [NaOH].

Comparing the rates R1 and R2, we can see that R2 is (1/9) times R1. Therefore, the rate of the reaction after adding three times water is 1/9th of the original rate.

Summary:
When three times water is added to the reaction mixture, the rate of the reaction CH3COOC2H5 + NaOH → CH3COONa + C2H5OH will decrease by a factor of 9. This is because the concentrations of both CH3COONa and NaOH decrease by a factor of 3, leading to a decrease in the rate of the reaction.

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