Mass transfer in chemical engineering

answer 2 only

I solved 1 and 3 right but I need the right answer for 2

use my method to solve

if no reaction (RA=0)

if steady state ( dca/dt=0)

I know it is spherical ccordinates and one dimensional but I got the answer wrong

here is my paper please correct my answer for question 2 only

(6 marks) Simplify the differential equation for mass transfer and Fick's flux equation according to the following assumptions: V.NA+ RA = 0 NA = -cDA yA + y (NA + NB) ar CA 1) Steady state Unimolecular diffusion inside a tank, one dimensional in z direction without reaction. 2) Steady state, equimolar counter diffusion from spherical tablet, one dimensional diffusion in O-direction. 3) Unsteady state Unimolecular diffusion in tube reactor, dilute system, two-dimensional diffusion (r, ) directions. NA.: : RA Rectangular coordinates NA NA, + + + at Cylindrical coordinates 1 N, + (rN,r) + + r Irar z Spherical coordinates [1 TN. (NAe sin 0) + + - RA ar r2 rin rsine 30 N.: , =RA (?NA.)* 1) Assumption: Steady State a 21 deado RA?! o o ZD + 2 QNAVO 22 dz 2017 LUMO 1- DZ-Direction ith No Rxn stile + ZNA+ 2013 Stardystate of deca JE Razo 7 no Rxn. 8x dydz Na: -DAR TWA+YA(NA+NB) eZ-D ANE NA- - CDAD SYA YA (NA+Y6) SONA = So da PRETENA - constant Naz-CDAS YA +YANA NAA NA-CDAB SYA dz NA - CDAB ISA222 (T-YA) ne buye) baba 108 -st.st 1-D - Direction. sphenal contrait coordinates and equimolar Counter diffusion PRE Y NA, -RA=0 ( tar) rsino do (NAN sin o)+ DYA St.st TO no Ran rsina de Nadsin Q.) = 0 sec 2) Assa se 70 ICA rsine do --D NA --DAB+XA (NA+NA O ot - RA= 8 LE - 3 Assump Ben unsteady State UND dilute system two dimensional. 1,2 cylindrical coordinztes RA=0 NA ZIC DAB VIA +XA (WA+NA ct or cr Na.r) ++ DNA, GOMA, 2) two direction [ I J (NA ANATA ro te (or M. r) + I NO SEA RA (rNA, r+ dr V. NA + - OLA It Ne + + st AM RE AV les XA0 dilute Systen OYA SYA Yo two.D + 30 3 A 5734 SU or is JF 14 JA NA-CDAB NA=GC DAN MAA) EC-Combining DY ADEVANDLE (5 15W 13 (SF