Question

For the rection $A⟶product,-\frac{d\left[A\right]}{dt}=k$ and at different time interval, [A] values are:

Time	0	5 min	10 min	15 min
$\left[A\right]$	$20mol$	$18mol$	$16mol$	$14mol$

At 20 minutes, rate will be :

• A. $12mol/min$
• B. $10mol/min$
• C. $8mol/min$
• D. $0.4mol/min$

Answer 1

Answer: (D)

$0.4mol/min$

Its a Zero Order Reaction

$k=\frac{\left[A_0\right]-\left[A\right]}{t}$

$k=\frac{\left[20\right]-\left[18\right]}{5}$ = $0.4$

Since Concentration of Reactant is independent of the rate for a zero order reaction, Rate = Rate constant.

$Rate=0.4mol/min$