Question

For the reaction $2A+B\to product,-\frac{d\left[A\right]}{dt}=k\left[A{]}^2\right[B]$. What will be the rate equation for $-\frac{d\left[B\right]}{dt}$?

• A. $\frac{1}{2}k\left[A{]}^2\right[B]$
• B. $k\left[A\right][B{]}^2$
• C. $k\left[2A{]}^2\right[B]$
• D. $k\left[A\right][B{]}^{1/2}$

Answer 1

The correct option is A $\frac{1}{2}k\left[A{]}^2\right[B]$

For reaction:

$2A+B\to product$

rate=$-\frac{1}{2}\frac{d\left[A\right]}{dt}=-\frac{d\left[B\right]}{dt}=\frac{d\left[product\right]}{dt}$

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

thus $-\frac{d\left[B\right]}{dt}=\frac{1}{2}k\left[A{]}^2\right[B]$

option A is correct