Question

For the reaction:
$2A\to \frac{1}{3}B$
Rate of disappearance of ‘A’ related to the rate of appearance of ‘B’ by the expression:

• A. $-\frac{d\left[A\right]}{dt}=\frac{-2}{3}\times \frac{d\left[B\right]}{dt}$
• B. $-\frac{d\left[A\right]}{dt}=\frac{+3}{2}\times \frac{d\left[B\right]}{dt}$
• C. $-\frac{d\left[A\right]}{dt}=-6\times \frac{d\left[B\right]}{dt}$
• D. $-\frac{d\left[A\right]}{dt}=+6\times \frac{d\left[B\right]}{dt}$
  

Answer 1

The correct option is D $-\frac{d\left[A\right]}{dt}=+6\times \frac{d\left[B\right]}{dt}$


For a reaction, if:
$aP+bQ\to cR+dS$

Overall rate $r$ can be expressed as:

$r=\frac{-1}{a}\times \frac{d\left[P\right]}{dt}=\frac{-1}{b}\times \frac{d\left[Q\right]}{dt}=\frac{+1}{c}\times \frac{d\left[R\right]}{dt}=\frac{+1}{d}\frac{d\left[S\right]}{dt}$

The given reaction is :

$2A\to \frac{1}{3}B$

$r=\frac{-1}{2}\times \frac{d\left[A\right]}{dt}=\frac{+3}{1}\times \frac{d\left[B\right]}{dt}$

$-\frac{d\left[A\right]}{dt}=+6\times \frac{d\left[B\right]}{dt}$