Tag: pseudo first order reaction

Questions Related to pseudo first order reaction

Consider the reaction represented by the equation represented by the equation
$CH _3Cl(g)\, +\, H _2O(g)\, \rightarrow\, CH _3OH(g)\, +\, HCl(g)$
These kinetic data were obtained for the given reaction concentrations

Initial conc (M) Initial conc (M) Initial rate of disappearance of
$[CH _3Cl]$ $[H _2O]$ $CH _3Cl\, (M\, s^{-1}$
0.2 0.2 1
0.4 0.2 2
0.4 0.4 8

If $H _2O$ is taken in large excess, the order of the reaction will be:

pseudo first order reaction order of reactions chemical kinetics electrochemistry and chemical kinetics chemistry

  1. 1

  2. 2

  3. 3

  4. None of these

Show answer
Correct Option: A
Explanation:

Comparing the rate law, the order w.r.t. $H _2O\, =\, 2$.
w.r.t. $[CH _3Cl]\, =\, 1$
$\therefore \, r\, =\, [CH _3Cl]\, [H _2O]^2$
Overall order = 1 + 2 = 3
If $H _2O$ is in excess, the order of the reaction will be 1.