In a reaction `2A rarr B` the concentration of A decreases from `0.3 mol L^(-1) to 0.2 mol L^(-1)` in 10 minutes. The reaction rate during trhis interval is mol `L^(-1) minute^(-1)`

Options

A. `0.01`
B. `-0.005`
C. `-0.01`
D. `0.005`

Answer

D

Explanation

Reaction rate=rate of disappearance of `A` per mole
`=-(1)/(2)((Delta[A])/(Deltat))=-(1)/(2)((0.2-0.3)molL^(-1))/(10min)`
`=0.005molL^(-1)min^(-1)`
Reaction rate is always a positive equantity. The negative sign simply indicates the fall in concentration of reaction `A` .