A first order reaction `A_(2)B_(2)(g) to 2A(g) + 2B(g)` at the temperature `400^(@)`C has the rate constant `k=2.0 xx 10^(-4)s^(-1)`. What percentage of `A_(2)B_(2)` is decomposed on heating for 900 seconds?

Explanation

For first order reaction, k`=2.303/t log a/(a-x), 2.0 xx 10^(-4)s^(-1)= 2.303/(900s)loga/(a-x)`
`loga/(a-x) = (2.0 xx 10^(-4)s^(-1)) xx (900s)/(2.303) = 0.0781`
`a/(a-x)= "Antilog" 0.0781 = 1.197, a=1.197a-1.197, x=0.197/1.197a = 0.1645a`
this means that `16.45%` of the initial concentration has changed into the products.