(i) A second-order or bimolecular reaction that mimics the behaviour of a first-order reaction is known as a pseudo first-order reaction. When one of the reactive materials is present in extreme excess or is kept at a constant concentration in relation to the other substance, the reaction takes place.
(ii) The amount of time needed for a reactant to achieve half of its starting concentration or pressure is known as the half-life of a reaction. A firstorder reaction's half-life is stable over time and concentration-independent.