The half-life of a first-order reaction is $850 \text{ s}$. The initial concentration of the reactant is $[R]_0 = 0.06 \text{ mol dm}^{-3}$. What concentration $[R]$ would remain after $t = 1200 \text{ s}$?

Consider the first-order gas-phase decomposition reaction given below:
$A_{(g)} \longrightarrow B_{(g)} + C_{(g)}$
The initial pressure of the system before the decomposition of $A$ was $P_i$. After time $t$,the total pressure of the system increased by $x \ units$ and became $P_t$. The rate constant $k$ for the reaction is given as:

Consider the two different first order reactions given below:
$A + B \rightarrow C$ (Reaction $1$)
$P \rightarrow Q$ (Reaction $2$)
The ratio of the half-life of Reaction $1$ : Reaction $2$ is $5 : 2$. If $t_1$ and $t_2$ represent the time taken to complete $2/3$ and $4/5$ of Reaction $1$ and Reaction $2$,respectively,then the value of the ratio $t_1 : t_2$ is $. . . . \times 10^{-1}$ (nearest integer).
[Given: $\log_{10}(3) = 0.477$ and $\log_{10}(5) = 0.699$]

If the half-life $(t_{1/2})$ of a reaction is $69.3 \ s$ and the rate constant $(k)$ is $10^{-2} \ s^{-1}$,then the order of the reaction is:

$A \rightarrow$ products is a first-order reaction. The following data is obtained for this reaction at $T \ K$. The value of $x : y$ is:

Rate $(\text{mol } L^{-1} \ \text{min}^{-1})$	$[A]$
$0.2$	$0.02 \ M$
$0.4$	$x \ M$
$1.0$	$y \ M$

For a first-order reaction $A \rightarrow B$,the rate of reaction is $2.0 \times 10^{-5} \, mol \, L^{-1} \, s^{-1}$ when the concentration of the reactant is $0.01 \, M$. The half-life of the reaction is ........ seconds.