A substance decomposes according to second order

rate law.If the rate constant is                              

6.8 x 10^-4   /mole/s,Calculate half - life of the

substance if the initial concentration is 0.05 mole/L.

In my opinion no one can solve this question

half life, t_1/2=1/ka .........for a second order reaction

put the values, t_1/2=29412 sec

but for second order

t i/2 = 1/k.a.n

But u haven't put the value of n

formula for T_1/2 for nth order reaction (n>=2) is

T_1/2= (2^n-1 - 1) / (n-1)k_n(a)^n-1

put the value of n here, n=2.

just apply the simple approach, -dA/dt = kAⁿ and integrate it.