For the reaction `2NO_(2)+F_(2)rarr 2NO_(2)F`, following mechanism has been provided:
`NO_(2)+F_(2) overset("slow")(rarr) NO_(2)F+F`
`NO_(2)+Foverset("fast")(rarr) NO_(2)F`
Thus rate expression of the above reaction can be writtens as:

Options

A. `r=K [NO_2]_2[F_2]`
B. `r=K[NO_3][F_3]`
C. `r=K [NO_2]`
D. `r=K [F_3] `

Answer

B

Explanation

Slowest step of mechansim decides the rate expression. Thus rate `= K [NO_(2)][F_(2)]` .