1.386 hours are required for the disappearance of 75% of a reactant of first-order reaction. What is the rate constant of the reaction?

Using 0 2.303log t A kt A 3 4 100 2.303log 100 75 t k 3 4 2.303 log4 x k t Put value, 1 2.303 log4 1hour 1.386 x k In terms of seconds 4 1 2.303 log4 2.7 10 sec 1.386 3600 x x x k