Which does not change with time for a first-order reaction?

The half-change time for a first order reaction is 20 min hence the rate constant for the reaction………….. .

The half-change time for a first order reaction is 20 min hence the rate constant for the reaction………….. .

In ____order reaction the rate of a reaction does not change with the concentration of the reactants.

Plot a graph of concentration of a reactant at time t, [ (a-x)] against time for a first order reaction .Here a = initial concentration of the reactant an x = change in concentration of the reactant at any time 1 during the reaction.