Question

The reaction `2NO + Br_(2) to 2NOBr`, obeys the following mechanism:
`NO + Br_(2) overset("fast")(hArr) NOBr_(2), NOBr_(2) + NO overset("Slow")(to) 2NOBr` The rate expression of the above reaction can be written as
A. `r = k [NO]^(2) [Br_(2)]_(2)`
B. `r = k [NO][Br_(2)]`
C. `r = k [NO][Br_(2)]`
D. `r = k [NOBr_(2)]`

Answer 1

Correct Answer - A
For slowest step : rate `= k [NOBr_(2)][NO]` …(i)
For equilibrium also `K_(c ) = ([NOBr_(2)])/([NO][Nr_(2)])`
Rate `= k [NO]^(2) [Br_(2)]`