Question

If for the reaction $A⟶B$
$rate=-\frac{d\left[A\right]}{dt}=2\frac{d\left[B\right]}{dt}$
then, rate law is

• A. $-\frac{d\left[A\right]}{dt}=k{\left[A\right]}^2$
• B. $\frac{d\left[B\right]}{dt}=k{\left[A\right]}^{}$
• C. $\frac{d\left[A\right]}{dt}=k{\left[A\right]}^2$
• D. $-\frac{d\left[B\right]}{dt}=k{\left[B\right]}^2$

Answer 1

Answer: (A)

$-\frac{d\left[A\right]}{dt}=k{\left[A\right]}^2$

$\frac{-d\left[A\right]}{dt}=2\frac{d\left[B\right]}{dt}$

$\frac{-d\left[A\right]}{2dt}=\frac{d\left[B\right]}{dt}$

The reaction is $2A⟶B$

Thus, rate law is

rate $\propto {\left[A\right]}^2$

$-\frac{d\left[A\right]}{dt}=k{\left[A\right]}^2$