The half-life of a first-order reaction is $1 \text{ hour}$. What fraction of the reactant will remain after $3 \text{ hours}$?

If the half-life period of a first order reaction is $138.6 \ minutes$,then the value of the decay constant for the reaction will be:

If the time required for $90\%$ completion of a first-order reaction is '$t$', what is the time required for $99.9\%$ completion of the reaction at the same temperature?

Consider the following first order gas phase reaction at constant temperature:
$A_{(g)} \rightarrow 2B_{(g)} + C_{(g)}$
If the total pressure of the gases is found to be $200 \ torr$ after $23 \ s$ and $300 \ torr$ upon the complete decomposition of $A$ after a very long time,then the rate constant of the given reaction is . . . . . . $\times 10^{-2} \ s^{-1}$ (nearest integer).
[Given: $\log_{10}(2) = 0.301$]

Rate of a first order reaction is $1.5 \times 10^{-2} \ mol \ L^{-1} \ minute^{-1}$ at $0.5 \ M$ concentration of reactant,calculate half life of reaction.

In the equation $Kt = \ln C_0 - \ln C_t$,the graph between $t$ and $\ln C_t$ is a .....