Question

The rate of the reaction
 $ C{H_3}COO{C_2}{H_5} + NaOH \to C{H_3}COONa + {C_2}{H_5}OH $ is given as
rate = K $ \left[ {C{H_3}COO{C_2}{H_5}} \right] $ [NaOH].
If three times water is added to the reaction mixture, what will be the rate of the reaction compared to the original rate?

Answer 1

Hint: This question is related to the concept of chemical kinetics. The rate of reaction is the rate or the speed at which a chemical reaction takes place. It is dependent on the concentration of reactants and becomes slower for dilute solutions.

Complete Step by step solution:
Chemical kinetics helps us in dealing with the different aspects of a chemical reaction. Kinetics refer to the rate of change of some quantity. As a reaction proceeds, concentration of the reactant decreases and concentration of the product increases.
The rate law which is also known as the rate equation, relates the rate of the reaction and the concentration of the reactant species involved in it.
The reaction rate constant determines the direction and the rate of the chemical reaction. The unit of the reaction rate constant depends upon the order of the reaction. The reaction rate constant is denoted by k.
The rate law expression is given as follows,
Rate (initially) = K $ \left[ {C{H_3}COO{C_2}{H_5}} \right] $ [NaOH] = r
When the water is added, the concentration of reaction becomes low and solution becomes dilute. So, when the reaction is diluted by three times that is three times water is added the concentration of each reactant becomes quarter that is it becomes one-fourth.
So, the new expression for rate of reaction is
Rate (after adding water) = $ \dfrac{{[C{H_3}COO{C_2}{H_5}]}}{4}\dfrac{{[NaOH]}}{4} $ = $ \dfrac{r}{{16}} $
(As we know, r that is initial rate = K $ \left[ {C{H_3}COO{C_2}{H_5}} \right] $ [NaOH])
So, the answer is that the final rate gets one-sixteenth of the initial rate.

Note:
Order is a relationship between rate of chemical reaction and concentration of the chemical species involved in it. It is experimentally determined for each reaction.