Q. Which expression is wrong for fist order reaction?
A) $k = \frac{2.303}{t}\log\left( \frac{A_{0}}{A_{t}} \right)$
B) $k = \frac{t}{2.303}\log\left( \frac{A_{0}}{A_{t}} \right)$
C) $- k = \frac{t}{2.303}\log\left( \frac{A_{t}}{A_{0}} \right)$
D) Rate=k[A]
Explanation
(b)
The rate for first order reaction is expressed as
$A \rightarrow products$
Rate= $- \frac{d\lbrack A\rbrack}{dt}$
Rate=k[A]
And the rate constant (k) is given as
$k = \frac{2.303}{t}\log\frac{\left\lbrack A_{0} \right\rbrack}{\left\lbrack A_{t} \right\rbrack}$
$or\ - k = \frac{t}{2.303}\log\frac{\left\lbrack A_{t} \right\rbrack}{\left\lbrack A_{0} \right\rbrack}$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.