The mass transfer co-efficient for a solid sphere of radius ‘a’ dissolving in a large volume of quiescent liquid, in which „D’ is the diffusivity of solute, is _____________________?

Related Mcqs:

1. According to the film theory of mass transfer, the mass transfer co-efficient is proportional to (where, D = molecular diffusivity) ?

   A. D B. D2 C. D0.5 D. 1/D...

2. The mass diffusivity, the thermal diffusivity and the eddy momentum diffusivity are same for, NPr = NSc = _________________?

   A. 1 B. 0.5 C. 10 D. 0...

3. For the gas absorption, the height of a transfer unit, based on the gas phase is given by (G: superficial molar gas velocity, L: superficial molar liquid velocity, FG: mass transfer co-efficient, moles/m2, a: interfacial area per unit volume of tower) ?

   A. G/(FG . a) B. FG/(G . a) C. (G . a)/FG D. L/(FG . G)...

4. Mass transfer co-efficient ‘K’ according to penetration theory varies with mass diffusivity as____________________?

   A. D0.5 B. D C. 1/D D. D1.5...

5. Experiments were conducted to determine the flux of a species A in a stagnant medium across a gas-liquid interface. The overall mass transfer co-efficient based on the liquid side for dilute systems for the above was estimated to be 4 × 10-3 kg mole/m2.s. The equilibrium data for the system is given as y = 2x. The flux across the interface (in kg mole/m2 .s) for bulk concentrations of A in gas phase and liquid phase as y = 0.4 and x = 0.01 respectively is _________________________?

   A. 5.6 × 10-4 B. 8.5 × 10-4 C. 5.6 × 10-3 D. 8.5 × 10-3...

6. In an interphase mass transfer process, the lesser the solubility of a given solute in a liquid, the higher are the chances that the transfer process will be_________________?

   A. Liquid phase resistance-controlled B. Gas phase resistance controlled C. Impossible D. Driven by a non-linear driving force...

7. In a liquid-liquid extraction, 10 kg of a solution containing 2 kg of solute C and 8 kg of solvent A is brought into contact with 10 kg of solvent B. Solvent A and B are completely immiscible in each other whereas solute C is soluble in both the solvents. The extraction process attains equilibrium. The equilibrium relationship between the two phases is Y* = 0.9X, where Y* is the kg of C/kg of B and X is kg of C/kg of A. Choose the correct answer?

   A. The entire amount of C is transferred to solvent B B. Less than 2 kg but more than 1 kg of C is transferred to solvent B C. Less than 1 kg of C is transferred to B D. No amount of C is transferred to B...

8. 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)) ?

   A. M(Xo – XF) B. M(Xo/XF) C. M ln(Xo/XF) D. MXo ln(Xo/XF)...

9. 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))_____________?

   A. M(Xo – XF) B. M(Xo/XF) C. M ln(Xo/XF) D. MXo ln(Xo/XF)...

10. For experimental determination of mass transfer co-efficient by wetted wall tower, the mass transfer area is___________________?

    A. Calculated B. Unknown C. Known D. Not required...