. Half life period of a reaction: The half life of a reaction is defined as the time required for the reactant concentration to reach one half its initial value. For a first order reaction, the half life is a constant i.e., it does not depend on the initial concentration. The rate constant for a first order reaction is given by k t = log [ [ ] at t t ; [ ] k t = log k t = log k = x0.
t t t k = XII U7 kinetics - Jerald XII U7 kinetics - Jerald - - - - Let us calculate the half life period for a zero order reaction. Rate constant, k = A t ] [ ] − at t t ; [ ] k = A A t k = A 2t t = A 2k Hence, in contrast to the half life of a first order reaction, the half life of a zero order reaction is directly proportional to the initial concentration of the reactant. More to know Half life for an n th order reaction involving reactant A and n ≠ t n n n ) [ k Example (i) A first order reaction takes hours for % completion. Calculate the time required for % completion.
(log = . ; log10 = ) Solution: For a first order reaction, k t log [A ] [A] .... ( ) Let [ M When t = t ; [A]=10M (given that t =8hours) % % t = t ; [A]=20M % k = log % t t k % log ( ) ( ) −−−−− Find the value of k using the given data k = log % t k = log