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If the rate constant for a first order reaction is k, the time (t) required for the completion of 99% of the reaction is given by:

1. t = 0.693/k
2. t = 6.909/k
3. t = 4.606/k
4. t = 2.303/k

Correct answer: t = 6.909/k

Solution

For a first-order reaction, the time for 99% completion is derived using the integrated rate law and the natural logarithm of the remaining 1%.

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