Descirbe some features of catalysis by zeolites.

Explanation

Fetures of catalysis by zeolite. (i) Zeolites are hydrated alumino-silicates ehich have a threedimensional network structure containing water molecules in their pores.
(ii) The size of the pores varies from 260 to 740 pm. Thus, only those molecules can be adosrbed in these pores and catalysed whose size is small enough to enter these pores. Hence, they act as molecular sieves or shape selective catalysts.
An important catalyst used in petoleum industry is `ZSM-5` (Zeolite sieve of molecular porority 5). It convertsalcohols into petrol by first dehydrating them to form a mixture of hydrocarbons.
Alcohols `overset(ZSM-5)underset("Dehydration")to` Hydrocarbons