Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Homework Help: Kinetics of acid-based and alkali-based catalysed reactions of esters

  1. Feb 25, 2008 #1
    1. The problem statement, all variables and given/known data

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

    2. Relevant equations

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

    3. 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.
  2. jcsd
  3. Feb 26, 2008 #2


    User Avatar
    Science Advisor
    Homework Helper
    Gold Member

    Would that be a saponification reaction you are talking about?
  4. Feb 26, 2008 #3
    oo yeah, i forgot to say it's about the hydrolysis of an ester, e.g. ethyl ethanoate.
  5. Mar 3, 2008 #4
    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.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook