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Question
Give one example of a pseudo first-order reaction.
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Solution 1
Hydrolysis of methyl acetate:
\[\ce{CH3COOCH_{3(aq)} + H2O_{(l)} -> CH3COOH_{(aq)} + CH3OH_{(aq)}}\]
Solution 2
Acid-catalysed hydrolysis of ethyl acetate
\[\ce{\underset{Ethyl acetate}{CH3COOC2H5} + H2O ->[H+] \underset{Acetic acid}{CH3COOH} + \underset{Ethyl alcohol}{C2H5OH}}\]
In this reaction, the concentration of water is so large that it practically remains constant.
The rate law of the reactions is
Rate = k0[CH3COOC2H5]
Hence, it is a pseudo-first-order reaction.
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