At $30^{\circ} \mathrm{C}$, the half life for the decomposition of $\mathrm{AB}_2$ is 200 s and is independent of the initial concentration of $A B_2$. The time required for $80 \%$ of the $A B_2$ to decompose is (Given: $\log 2=0.30 ; \log 3=0.48$ )
