Two substances R and S decompose in solution independently, both following first order kinetics. The rate constant of R is twice that of S . In an experiment, the solution initially contained 0.5 millimoles of R and 0.25 of S . The molariti

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Two substances R and S decompose in solution independently, both following first order kinetics. The rate constant of R is twice that of S . In an experiment, the solution initially contained 0.5 millimoles of R and 0.25 of S . The molarities of R and S will be equal just at the end of time equal to

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Correct answer: A. twice the half life of R

Substance R Substance S 2 k k rate constant t _ 1 / 2 = n t _ 1 / 2 where n = number of half life period Amount of R left = 0.5 (2)^ T / t _ / 2 Amount of S left = 0.25 (2)^ T / 2 t / 2 Equating both 0.5 0.25 = (2)^ T / t _ 1 / 2 (2)^ T / 2 t _ 1 / 2 or 2=(2)^ T / t _ 1 / 2 T =2 t _ 1 / 2 2 t _ 1 / 2 is half life of S and twice the half -life of R

Two substances R and S decompose in solution independently, both following first order kinetics. The rate constant of R is twice that of S . In an experiment, the solution initially contained 0.5 millimoles of R and 0.25 of S . The molarities of R and S will be equal just at the end of time equal to

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