Q$.4($a$)"$In a catalyst pellet, if the rate of diffusion through the pores is much higher than the rate of reaction, then the vaide of Thiele modulus will approach unity". Justify this statement

$($b$)$ Show that for a first order irreversible reaction under isothermal condition on a rectangular catalyst particle, effectiveness factor is given by

$=(\frac{\text{I}}{M_{}})*tanh{M}_T$