Question

For the reaction $\frac{1}{2}A\to 2B$, the rate of disappearance of ‘A’ is related to the rate of appearance of ‘B’ by the expression:

• A. $-\frac{d\left[A\right]}{dt}=\frac{1}{2}\frac{d\left[B\right]}{dt}$
  
• B. $-\frac{d\left[A\right]}{dt}=\frac{1}{4}\frac{d\left[B\right]}{dt}$
  
• C. $-\frac{d\left[A\right]}{dt}=\frac{d\left[B\right]}{dt}$
  
• D. $-\frac{d\left[A\right]}{dt}=4\frac{d\left[B\right]}{dt}$

Answer 1

The correct option is B $-\frac{d\left[A\right]}{dt}=\frac{1}{4}\frac{d\left[B\right]}{dt}$


$\frac{1}{2}A\to 2B-\frac{d\left[A\right]}{dt}\times \frac{2}{1}=\frac{1}{2}\frac{d\left[B\right]}{dt}-\frac{d\left[A\right]}{dt}=\frac{1}{4}\frac{d\left[B\right]}{dt}$