# Indicate the order of reaction for each of the following observations.?

Indicate the order of reaction for each of the following observations.?

• a.half life gets shorter as initial concentration is increased ….this means that half life is inversely proportional to initial concentration …means this is the case of second order reaction…

half life = 1/[Ao]k

b.we know that for a first order reaction k = 2.303/t log [Ao]/[A]

where [Ao] = initial concentration

[A] = concentration at any time t

and k is rate constant…

so, kt/2.303 = log [Ao]/[A]

kt/2.303 = log [Ao] – log [A]

log [A] = -kt/2.303 + log [Ao]

this equation is of the form y = mx (equation of straight line )…this if log [A] values are plotted against time ‘t’ the graph obtained will be a straight line

intercept made on y axis would be log [Ao] and slope of line will be equal to -k/2.303..

c.for zero order reaction : half life = [ao]/2k..half life is directly proportional to initial concentration ….so as initial concentration increases half life also increases…