Question

Which statements is/are not correct about Ist order reaction?

• A. They take an infinitesimally long time for the reaction to go to completion.
• B. The decrease in $t_{1/2}$ is exponential for Ist order reaction.
• C. For all practical purposes they are supposed to be completed after 10 halves.
• D. The degree of dissociation of a reactant obeying Ist order in given by $r^{-\lambda t}$

Answer 1

The correct option is D The degree of dissociation of a reactant obeying Ist order in given by $r^{-\lambda t}$

As we know,
$N=N_0{e}^{-\lambda t}$
$\alpha =\frac{N_0-N}{N_0}=\frac{N_0-N_0{e}^{\lambda t}}{N_0}=1-e^{-\lambda t}$