Chemical Engineering MCQs

‘Absorption with chemical reaction’ is involved in the removal of

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Carbon dioxide from gaseous stream using alkaline solution
Benzol from coke oven gas using solar oil/wash oil
Ammonia from coke oven gas using refrigerated water
Tar from coke oven gas in primary gas coolers using chilled water
✅ The correct answer is option A.

Mean residence time is equal to the space time, when

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The feed rate is measured at temperature and pressure in the reactor
The temperature, pressure and the density of reaction mixture remains constant throughout the reactor
There is no change in number of moles in gaseous reaction
All of the above
✅ The correct answer is option D.

A solid is being dried in the linear drying rate regime from moisture content Xo to XF. The drying rate is zero at X = 0 and the critical moisture content is the same as the initial moisture Xo. The drying time for M = (Ls/ARc) is (where, L = total mass of dry solid, A = total surface area for drying Rc = Constant maximum drying rate per unit area X = moisture content (in mass of water/mass of dry solids)

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M(Xo – XF)
M(Xo/XF)
M ln(Xo/XF)
MXo ln(Xo/XF)
✅ The correct answer is option D.

An irreversible first order reaction is being carried out in a CSTR and PFR of same volume. The liquid flow rates are same. The relative conversion will

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Be more in CSTR than in PFR
Be more in PFR than in CSTR
Be same in both cases
Depend on the temperature
✅ The correct answer is option B.