Which one of the following formulas represents a first-order reaction?

The plot of $t_{1/2}$ versus $[R]_0$ for a reaction is a straight line parallel to the $x$-axis. The unit for the rate constant of this reaction is:

If the decomposition reaction $A_{(g)} \to B_{(g)}$ follows first-order kinetics,then the graph of the rate of formation $(R)$ of $B$ against time $t$ will be:

For a first-order reaction $A \rightarrow \text{product}$, the rate constant is $k = 2 \times 10^{-2} \text{ s}^{-1}$. If the initial concentration of $A$ is $[A]_0 = 1.0 \text{ mol dm}^{-3}$, find the value of $\log \frac{1}{[A]_t}$ after $t = 100 \text{ s}$.

For the first order reaction $2 N_2O_{5(g)} \rightarrow 4 NO_{2(g)} + O_{2(g)}$,which of the following statements are correct?
$A.$ The concentration of the reactant decreases exponentially with time.
$B.$ The half-life of the reaction decreases with increasing temperature.
$C.$ The half-life of the reaction depends on the initial concentration of the reactant.
$D.$ The reaction proceeds to $99.6 \%$ completion in eight half-life durations.

In a first order reaction,the concentration of the reactant is reduced to $1/8$ of the initial concentration in $75 \ minutes$. The $t_{1/2}$ of the reaction (in minutes) is $(\log 2 = 0.30, \log 3 = 0.47, \log 4 = 0.60)$.