Gas Solid Reaction (Julian Szekely, James W. Evans, Hong Yong Sohn) is a good reference for gas solid reaction. In the section of chemical reaction control, that I have attached here, the equation converted to dimensionless form to calculate equation X according to t.
for calculate this equation, I must convert it to dimensionless form or there is another solution too?
A(g) + bB(s) ___> cC(g)