Which of the following is an example of pseudo unimolecular reaction ?

Options

A. `CH_(3)COOCH_(3) + H_(2)O overset(H^(+))rarrCH_(3)COOH+CH_(3)OH`
B. `CH_(3)COOCH_(3) + H_(2)O overset(OH^(-))rarrCH_(3)COOH+CH_(3)OH`
C. `2FeCl_(3) +SnCl_(2)rarr SnCl_(4) + 2FeCl_(2)`
D. `NaOH +HCl rarr NaCl + H_(2)O`

Answer

A

Explanation

When in any chemical reaction, one of the reactant is present in large excess, then the second-order reaction becomes first-order reaction and is known as pseudo unimolecular reaction e.g.,
`CH_(3)COOCH_(3) + H_(2)O overset(H^(+))(rarr) CH_(3) COOH + CH_(3) OH`
in this reaction molecularity is `2` but order of reaction is found to be first order experimentally, so it is an example of pseudo unimolecular reaction.