Question #45035

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Answer 1 · 2017-04-12T18:30:51

We can understand it through the derivation of half life for 1st order reaction.

Equation for 1st order reaction is:

#k = 2.303/t × log_10(["A"_0]/["A"])#

Where,
#k# = rate constant
#["A"]# = concentration after time #t#
#["A"_0]# = initial concentration

For half life, #["A"]# = #["A"_0]/2#

Therefore,
#k = 2.303/"t"_½ × log_10( ["A"_0]/(["A"_0]/2))#

#k = 2.303/"t"_½× log_10(2)#

#k = 2.303/"t"_½ × 0.301#

#k = 0.693/"t"_½#

Therefore, the equation for half life of first order reaction is independent of concentration and thus independent of stoichiometric ratio.