The gas phase reaction `2NO_(2)+O_(3)rarrN_(2)O_(5)+O_(2)` has the rate constant `k = 2.0xx10^(-4) dm^(3) mol^(-1) s^(-1)` at 300 K. The order of the reaction is

Options

A. 0
B. 3
C. 2
D. 1

Answer

C

Explanation

The units of rate constant depend on th eoverall reaction order. Units of rate constant, we can decide the overall reaction order. If `n` is the overall order of th ereaction, then units of rate constant are given as
`["Concentration"]^(^(1-n))[sec]^(-1)`
`[moldm^(-3)]^(1-n)[sec]^(-1)`
Equating the units of given rate constant with the general expression we get, `dm^(3)mol^(-1)s^(-1)=[moldm^(-3)]^(1-n)[sec]^(-1)`
`n=2`