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JEE MainChemistryChemical Kinetics

For a first-order chemical reaction, the half-life is 30 minutes. The time required for 90 % completion of the reaction is _____ minutes. [Given : 2 = 0.3 ]

Correct answer

100

Step-by-step solution

For a first-order reaction, the rate constant k is given by: k = 2.303 2 t_ 1/2 The time t required for 90 % completion is: t = 2.303 k ( 100 100 - 90 ) t = 2.303 k 10 t = 2.303 k 1 Substituting the expression for k : t = 2.303 2.303 2 t_ 1/2 t = t_ 1/2 2 Given t_ 1/2 = 30 minutes and 2 = 0.3 : t = 30 0.3 = 100 minutes. Answer: 100

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