Highly purified tetrachlorosilane (SiCl4) gas is reacted with hydrogen gas (H2) to produce electronic-grade polycrystalline silicon at 800oC and 1.5×105 P according to the equation: 4()+2H2()→()+4H ()

There are concerns that the reaction experiences diffusional limitations at the growing Si solid surface. Estimate the molecular diffusion coefficient for:

a. SiCl4 in H2
b. SiCl4 in a gas phase mixture containing 40 mol%