For a first-order reaction:

Both (1) and (2)

The correct option is (4) Both (1) The degree of dissociation is equal to (1– e^–kt) and (2) The pre-exponential factor in the Arrhenius
the equation has the dimensions of time t^–1.

For a first-order reaction:

(1) The degree of dissociation is equal to $(1 - e^{-kt})$. The degree of dissociation represents the fraction of the reactant that has undergone reaction at a given time. It is calculated as 1 minus the exponential decay term $e^{-kt}$, where $k$ is the rate constant and $t$ is the time.

(2) The pre-exponential factor in the Arrhenius equation has the dimensions of time $t^{-1}$. The Arrhenius equation relates the rate constant ($k$) to temperature ($T$) and the pre-exponential factor ($A$):

$k = A \cdot e^{-\frac{E_a}{RT}}$

The pre-exponential factor ($A$) has the dimensions of rate constant divided by the exponential term, which is equal to $t^{-1}$.

Therefore, both statements (1) and (2) are correct for a first-order reaction.