The conversion of a first-order liquid phase reaction A → B in a single CSTR is 50%. If an identical CSTR is added in series, what will be the percentage conversion at the exit of the second reactor_____________________?
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Answer: B. 75
Explanation
Achieving 50 percent conversion in the first continuous stirred tank reactor leaves an unconverted fraction of 0.5. Passing this remaining reactant stream into an identical second CSTR converts another 50 percent of the remainder. The overall unconverted fraction becomes 0.5 multiplied by 0.5, yielding 0.25, which represents 75 percent conversion. Continuous stirred tank reactors feature complete internal fluid mixing resulting in uniform exit concentrations. Staging multiple reactors in series allows achieving higher overall conversions than a single large vessel. First-order liquid phase reaction equations simplify performance calculations for continuous stirred tank reactor trains.
Chemical processing plants often utilize multiple CSTRs in series to scale up production capacity efficiently. Calculating reactor trains helps engineers optimize capital equipment costs versus desired product conversion yields. Staged reaction systems provide better control over reaction times and thermal profiles in fluid processing. Option A suggesting 60 percent conversion underestimates the cumulative efficiency of staged continuous reactors. Option C proposing 90 percent conversion would require more than two reactors of identical volume. Option D claiming 100 percent conversion violates the asymptotic conversion limits of continuous stirred tank reactors.
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- Engineering
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- Chemical Engineering
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- medium
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