Sagot :
The half-life of the reaction is 101.9 min
First order reaction
When a reaction's pace and reactant concentration are inversely correlated, the process is known as a first-order reaction. To put it another way, the reaction rate doubles when the concentration does. One or two reactants can be present in a first-order reaction, as in the case of the decomposition process.
The half-life of first-order reaction:-
The amount of time it takes for the initial concentration of the reactant(s) to decrease by half is known as the half-life of a chemical reaction (abbreviated as "t1/2").
Calculation:-
a→b
25% reacted means 75% remains
t=42 min
Rate constant
k=(2.303/t)(log a/a-x)
k=(2.303/42)(log 100/100-25 )
k=(0.054) (log 100/75)
k=(0.054)(0.1249)
k=0.0068 per min
half life
t1/2=(0.693/k)
=(0.693/0.0068)
=101.9 min
Learn more about first order reaction here :-
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