Conisder a mechanism in which a single reactant profuces several Products by the following parallel first order reactions :
`A overset(k_(1))rarrB, A overset(k_(2))rarrC A overset(k_(3))rarrD`
Write the rate expresison for `[A]`.

Explanation

`(-d[A])/(dt)=k_(1)[A]+k_(2)[A]+k_(3)[A]`
`=(k_(1)+k_(2)+k_(3))[A]`
`=k[A]`