Question

From following which is the correct chemical formula of zeolite?
(A)${{K}_{2}}A{{l}_{2}}S{{i}_{2}}{{O}_{8}}.x{{H}_{2}}O$
(B)$C{{a}_{2}}A{{l}_{2}}S{{i}_{2}}{{O}_{8}}$
(C)$N{{a}_{2}}A{{l}_{2}}S{{i}_{2}}{{O}_{8}}.x{{H}_{2}}O$
(D)$N{{a}_{2}}(N{{a}_{4}}{{(P{{O}_{3}})}_{6}})$

Answer 1

The Si atom is replaced by the Aluminium atoms from the three dimensional structure of silicates.There are water molecules present in the crystalline structure of zeolite.

Complete step-by-step answer: In the question it is asked to write the chemical formula of zeolite. Before going into the solution part let’s discuss zeolites.
-A mineral consisting of silicon and oxygen ions in a tetrahedral unit $SiO_{4}^{4-}$links together in different patterns to generate a 3D structure called as the silicates.
When the silicon atom (Si) present in the silicates are replaced with aluminium ions ($\text{A}{{\text{l}}^{\text{3+}}}$), the final structure obtained is called as aluminosilicates which will be negatively charged structure and to nullify this charge or balance this overall charge cations like sodium ion ($N{{a}^{+}}$), potassium ion (${{K}^{+}}$) and aluminium ion ($\text{A}{{\text{l}}^{\text{3+}}}$) etc. incorporated with the aluminosilicates unit and this yields a 3D structure.
The three dimensional crystalline structure formed is called as the zeolite and it has a general formula of zeolite is${{M}_{{}^{2}/{}_{n}}}O.A{{l}_{2}}{{O}_{3}}.xSi{{O}_{2}}.y{{H}_{2}}O$.
Generally we say zeolites as those species with sodium as the cations, sodium aluminosilicates are generally termed as the zeolites which occur naturally.
And hence from the above given option we could say that the chemical formula of zeolite is$N{{a}_{2}}A{{l}_{2}}S{{i}_{2}}{{O}_{8}}.x{{H}_{2}}O$ .
Therefore the correct option for the question given is option (C).

Additional Information:
Zeolites have a regular three dimensional framework and it has a porous structure in which the monovalent sodium ions and the water molecules are weakly bonded. Because of this porous structure they are used as the catalysts and as the ion exchange resins for the softening of hard water.

Note: Feldspar is also formed by the removal of Si atoms, from the aluminosilicates and they have the general formulae$\text{A}{{\text{T}}_{\text{4}}}{{\text{O}}_{\text{8}}}$, where A = Na, K, Ca and T represents Si and Al atoms having a ratio of $Si:Al$ranging from $3:1$ to $1:1$.Generally potassium aluminosilicates are referred as the Feldspar.