Q.Describe some features of catalysis by zeolites.

Step 1 – What zeolites are. Zeolites are hydrated aluminosilicates with a general open framework of $(AlO_4)$ and $(SiO_4)$ units, giving a honeycomb-like structure riddled with cavities and pores of fixed, uniform size (typically 260–740 pm).

Step 2 – Shape-selective action. The catalytic reaction depends on the size of the pores/cavities — only reactant molecules small enough to enter the pores (and products small enough to leave) take part. Hence zeolite catalysis is shape-selective catalysis.

Step 3 – Activation. They are activated by heating to remove the water of hydration, exposing the internal cavities where catalysis occurs. …

Describe zeolite structure (honeycomb aluminosilicate, uniform pores), explain shape selectivity from pore size, and g …

• Calling zeolites simple silicates rather than hydrated aluminosilicates. …