Question

In a hydrolysis reaction , 5g ethyl acetate is hydrolysed in presence of dilute HCI In $300$ minutes . If the reaction is of first orderand the initial concentration of ethyl acetate is $22g/l.$ calculate the rate constant of the reaction.

Answer 1

For First order reaction

$K=\frac{2.303}{t}\log \frac{A_o}{A}$

Initial concentration, $A_o=22g/L=\frac{22}{88}mole/L$

$5g$ of ethyl acetate has been hydrolysed.

So, $\frac{5}{88}$ moles of ethyl acetate has been hydrolysed.

So, number of moles remaining in the solution$=\frac{22}{88}-\frac{5}{88}=\frac{17}{88}$

$\Rightarrow K=\frac{2.303}{t}\log \frac{22/88}{17/88}$

$\Rightarrow K=\frac{2.303}{300min}\log \frac{22}{17}$

$K=8.6\times {10}^{-4}mi{n}^{-1}$

This is the Rate constant.