For a reaction $\text{A} \longrightarrow$ product, $k = 2 \times 10^{-2}\ \text{s}^{-1}$. If the initial concentration of A is $1.0\ \text{mol dm}^{-3}$ find the value of $\log \dfrac{1}{[A]_t}$ after 100 second ?

In a first order reaction 20 millimole of reactant is lowered to 10 millimole in $0.3010$ minute. Find rate constant of the reaction?

For the reaction $2\text{NOBr}_{(g)} \longrightarrow 2\text{NO}_{(g)} + \text{Br}_{2(g)}$, rate law is $r = k[\text{NOBr}]^2$. Rate constant is $1.62\ \text{M s}^{-1}$ and concentration of NOBr is $5 \times 10^{-3}\ \text{M}$,
What is rate of reaction?

Which of the following reactions has of overall order $1.5$ ?