rate of a reaction = k [a]^n

 

 where n is the order

 

 

forward reaction is 0 order and back ward reaction is 2nd order

 

for a 0 order reaction rate = k [a]^0

 

 for 2nd order reaction rate =k[a]^2

 

 

let equilbrium concetration  of M be x and 1-x due to backward reaction 

 

for forward reaction rate =kf

for backward reaction rate = kb [ x/(1-x)]^2

 

at equilibrium ,  rate of forward reaction = rate of backward reaction

 

 kf /kb   = [x/ (1-x) ]^2

 

x = 0.114

 

0.114 M is the equilibrium concentration of M