Q. The rate constant of a zero order reaction is $0.2\ mol\ {dm}^{- 3}\ h^{- 1}.$ If the concentration of the reactant after $30\$min is$\ 0.05\ mol\ {dm}^{- 3}.$ Then its initial concentration would be
A) $0.01\ mol\ {dm}^{- 3}$
B) $0.15\ mol\ {dm}^{- 3}$
C) $0.25\ mol\ {dm}^{- 3}$
D) $4.00\ mol\ {dm}^{- 3}$
Explanation
(b)
For zero order reaction
$x = kt$
$= 0.2\ mol\ {dm}^{- 3}\ h^{- 1} \times \frac{30}{60}\ h$
$= 0.1\ mol\ {dm}^{- 3}$
Now, concentration $= 0.05\ mol\ {dm}^{- 3}$
Hence, initial concentration $= 0.1 + 0.05 = 0.15\ mol\ {dm}^{- 3}$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.