Question

The half life for the decomposition of gaseous compound $A$ is $240s$ when the gaseous pressure was $500$ Torr initially. When the pressure was $250$ Torr, the half life was found to be $4.0\min$. The order of the reaction is....... (Nearest integer)

Answer 1

Answer: 1

${\left(t_{1/2}\right)}_{500\text{ torr }}=240\sec =4\min$.
${\left(t_{1/2}\right)}_{250\text{ torr }}=4\min$.
$t_{1/2}\propto a^{1-n}$
As $t_{1/2}$ is independent of initial pressure. Hence, order is $1st$ order.