CBSE Class 11-science Answered

Zeolite is a naturally occurring mineral group consisting of over 50 different minerals.  Made of a special crystalline structure that is porous but remains rigid in the presence of water, zeolites can be adapted for a variety of uses.

Zeolites have a porous structure that can accommodate a wide variety of cations, such as Na⁺, K⁺, Ca²⁺, Mg²⁺ and others. These positive ions are rather loosely held and can readily be exchanged for others in a contact solution. Some of the more common mineral zeolites areanalcime, chabazite, clinoptilolite, heulandite, natrolite, phillipsite, and stilbite. An example mineral formula is: Na₂Al₂Si₃O₁₀·2H₂O, the formula for natrolite.

Zeolites are being very widely used as catalyst in petrochemical industries for cracking of hydrocarbons and isomerization. An important zeolite catalyst used in the petroleum industry is ZSM – 5. It converts alcohols directly into gasoline by first dehydrating them so that a mixture of hydrocarbons is formed.