Which one of the following statements about the zeolites is false ?

Options

A. They are used as cation exchangers
B. They have open structure which enables them to take up small molecules.
C. Zeolites are aluminosilicates having three dimensional network.
D. Some of the `SiO_4^(4-)` units are replaced by `AlO_4^(5-)` and `AlO_6^(9-)` ions in zeolites.

Answer

D

Explanation

Zeolite are microporous crystalline solid with well defined structure. They contain silicon, aluminium and oxygen in their framework and cations, water and other molecules within their pores. The general formula of zeolite is `M_(x//y) [(AlO_2)_x (SiO_2)_y]. mH_2O` .