Project ForgeProcess Calculations
Laws of Thermodynamics
GATE 2017
Hard
TBA+EtOH⇌ETBE+Water, Kc=1. Initially 74g TBA mixed with 100g of 46wt% aqueous ethanol (MW: TBA 74, EtOH 46, ETBE 102, Water 18). The mass of ETBE at equilibrium, rounded to 1 decimal place, is
20.4 g(± 0.5 accepted)
Explanation
Initial: TBA=1mol, EtOH=1mol, Water=54g/18=3mol (already present in the aqueous feed), ETBE=0. Kc=[ξ(3+ξ)]/[(1−ξ)²]=1 ⟹ 3ξ+ξ²=1−2ξ+ξ² ⟹ 5ξ=1 ⟹ ξ=0.2. Mass ETBE=0.2×102=20.4g.
Source: GATE CH 2017 (2017)
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