Project ForgeChemical Reaction Engineering
Ideal Reactor Design
GATE 2016
Hard
A⇌B (elementary, first-order both directions) in an isothermal CSTR, CA0=10, CB0=0 mol/L. At τ=1s, CA=8; at τ=5s, CA=5. The forward rate constant (s⁻¹), rounded to 3 decimal places, is
0.267 s^-1(± 0.015 accepted)
Explanation
At τ=1: (10−8)/1=2=8k1−2k2. At τ=5: (10−5)/5=1=5(k1−k2) ⟹ k1−k2=0.2. Solving: 4k1−k2=1 with k2=k1−0.2 gives 3k1=0.8 ⟹ k1=0.267 s⁻¹.
Source: GATE CH 2016 (2016)
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