Kinetics of acid-based and alkali-based catalysed reactions of esters

[Kushal]

Homework Statement

Why is the acid based catalysed reaction of esters first order while the akaline based catalysed reaction is second order.

Homework Equations

rate is proportional to [ester]^a [water]^b

The Attempt at a Solution

i know that a fisrt order is proportional to only one substance, here it is the ester. and most probably the second order is proportional to both the ester and the OH-. now i can't explain why.

 

[chemisttree]

Would that be a saponification reaction you are talking about?

 

[Kushal]

oo yeah, i forgot to say it's about the hydrolysis of an ester, e.g. ethyl ethanoate.

 

[Kushal]

well... i got the answer...

acid hydrolysis is first order with respect to the ester, and zero order with respect to the H+. overall order is 1.

alkaline hydrolysis is first order with respect to ester and first order with respect to OH-. overall order is 2.