Keen observation of the rates of reaction about the series of steps leading to the formation of products is called the reaction mechanism . The reaction between H_(2) and I_(2) to form hydrogen iodide was originally postulated as a simple one step reaction H_(2) + I_(2) to 2 HI Rate = k [H_(2)][I_(2)] but the formation of HI has been explained on the basis of the following mechanism ({:( I_(2) , to , 2 I "(fast)" , ... (i) ), ( H_(2) + I , to , H_(2) I "(fast)" , ... (ii)) , (H_(2) I + I , to , 2HI "(slow)" , ... (iii) ):})/("overall" H_(2) + I_(2) to 2 HI For the reaction 2NO_(2) + F_(2) to 2 NO_(2) F following mechanism has been provided NO_(2) + F_(2) overset("slow")(to) NO_(2)F + F NO_(2) + F overset("fast")(to) NO_(2)F Thus rate expression of the above reaction can be written as

Keen observation of the rates of reaction about the series of steps le

1.	Keen observation of the rates of reaction about the series of steps leading to the formation of products is called the reaction mechanism . The reaction between H_(2) and I_(2) to form hydrogen iodide was originally postulated as a simple one step reaction H_(2) + I_(2) to 2 HI Rate = k [H_(2)][I_(2)] but the formation of HI has been explained on the basis of the following mechanism ({:( I_(2) , to , 2 I "(fast)" , ... (i) ), ( H_(2) + I , to , H_(2) I "(fast)" , ... (ii)) , (H_(2) I + I , to , 2HI "(slow)" , ... (iii) ):})/("overall" H_(2) + I_(2) to 2 HI For the reaction 2NO_(2) + F_(2) to 2 NO_(2) F following mechanism has been provided NO_(2) + F_(2) overset("slow")(to) NO_(2)F + F NO_(2) + F overset("fast")(to) NO_(2)F Thus rate expression of the above reaction can be written as
Answer» `r = k[NO_(2)]^(2) [F_(2)]` `r = k[NO_(2)]` `r = k [NO_(2)][F_(2)]` `r = k [F_(2)]` Solution :Rate is GIVEN by the SLOWEST step of the REACTION so rate is r = `k[NO_(2)][F_(2)]`.