For a reaction `(1)/(2) A to 2B,` the rate of disappearance of 'A' is related to the rate of appearance of 'B' by the expression-

Options

A. `- (d[A])/( dt) = (1)/(2) (d[B])/( dt)`
B. `- (d [A])/(dt) = (1)/(4) (d[B])/(dt)`
C. `- (d [A])/(dt) = (d[B])/(dt)`
D. `- (d [A])/(dt) = 4 (d [B])/(dt)`

Answer

B

Explanation

`(1)/(2) A to 2 B`
Remember for a ` A to b B`
`- (1)/(a) (d [A])/(dt) = (1)/(b) (d [B])/(dt)=` Rate of reaction
For the given reaction
`- (2d [A])/(dt) = (1)/(2) (d [B])/(dt)=`Rate of reaction
Rate of disppearance of A
`= - (d [A])/(dt) = (1 )/(2 xx 2) (d [B])/( dt)`
`= (1)/(4) (d [B])/( dt)`