Question

Which one of the following statement about the zeolite is false?

• A. They are used as cation exchangers
• B. Some of the $Si{O}_4^{4-}$ units are replaced by $Al{O}_4^{5-}$ and $Al{O}_6^{9-}$ ions in zeolite
• C. They have open structure which enables them to take up small molecules
• D. Zeolite are aluminosilicates having three dimensional structures

Answer 1

The correct option is B Some of the $Si{O}_4^{4-}$ units are replaced by $Al{O}_4^{5-}$ and $Al{O}_6^{9-}$ ions in zeolite

Answer:-

(A) Zeolites are natural ion exchangers. For example, permutit water softeners are sodium zeolites. They take up calcium ions from hard water and release sodium ions in water.

Thus, the statement A is correct.

(B) In zeolites, some of the the ${Si}^{4+}$ ions may be replaced by ${Al}^{3+}$. This results in unbalanced anionic charge. To maintain electrical neutrality, positive ions must be introduced. Thus, the statement B is incorrect.

(C) Zeolites are like molecular sieves. They trap small molecules such as water, ammonia and carbon dioxide in their interstices.

Thus, the option C is correct.

(D) zeolites are aluminosilicates having three dimensional network. They are termed aluminosilicates because, some of the the ${Si}^{4+}$ ions may be replaced by ${Al}^{3+}$.

Thus, the option D is correct.

$\Rightarrow$ Thus, the option B is false.