Answer :
Final answer:
To find the time needed for 80% completion of a first-order reaction, use the equation ln(C0/C) = kt and substitute the given values to solve for t. the correct answer is a) 92.4 min.
Explanation:
To find the time needed for 80% completion of a first-order reaction, we can use the equation ln(C0/C) = kt, where C0 is the initial concentration, C is the concentration at a given time, k is the rate constant, and t is the time. In this case, since we're given the time for 50% completion, we can substitute the given values into the equation and solve for t when C/C0 = 0.8.
ln(0.5) = k(69.3)
ln(0.8) = k(t)
By rearranging the second equation and substituting the given value for k, we can solve for t:
t = ln(0.8)/k = 0.3010/1.0 × 10^7 = 0.0301 min
Therefore, the time needed for 80% completion of the reaction is approximately 0.0301 min.
