AB----> A + B
rate= k(ab)^2
by use of integrated second order rate law
1(/Ab)t = 1/AB)0 + Kt
t= time
k=constant
(AB)0 =initial concentration
(AB)t= final concetration
1/(ab)t= 1/1.5 + 0.20 x12.9 = 3.35
1/(ab)t = 3.25 multiply both side by ( ab)t
1= 3.25(ab)t divide both side by 3.25
(ab)t is therefore=0.308
