Thermal decomposition of dinitrogen pentoxide takes place by the following mechanism :
`N_2O_5 overset("Slow")(rarr)NO_2 + NO_3`
`N_2O_5 = NO_3 overset("Fast")(rarr) 3NO_2 +O_2`
Write the rate'expression and order of the reaction.

Explanation

`N_2O_5 overset("Slow")(rarr)NO_2 + NO_3`
`N_2O_5 = NO_3 overset("Fast")(rarr) 3NO_2 +O_2`
In a multistep reaction the slowest step is the rate determining step. Therefore, the rate of the complete reaction will depend upon first step i.e,
`N_2O_5 overset("Slow")(rarr)NO_2 + NO_3`
`therefore` rate=`k[N_2O_5]`
Order=1