Question

Which of the following statements are true for zeolites?
1.They are formed by the replacement of some of the silicon atoms of the $Si{O}_2$ lattice, by say, aluminum.
2. They have a more closed structure than feldspar.
3. They can absorb $C{O}_2$, $N{H}_3$ and $EtOH$.
4. They can separate straight chain hydrocarbons from a mixture containing both straight chain and branched chain hydrocarbons.

• A. $1,2$ and $3$ are correct
• B. $1,3$ and $4$ are correct
• C. $1,2$ and $4$ are correct
• D. $2,3$ and $4$ are correct

Answer 1

Answer: (B)

$1,3$ and $4$ are correct

1. When some of the silicon atoms present in the crystal lattice of silica are replaced by metals such as $Al$, zeolites are formed.
Thus, the statement 1 is correct.
2. The structure of feldspar is more close than that of zeolites.
Thus, the statement 2 is incorrect.
3. Zeolites are like molecular sieves. They trap small molecules such as water, ammonia and carbon dioxide in their interstices.
Thus, the statement 3 is correct.
4. They can separate straight chain hydrocarbons from a mixture containing both straight chain and branched chain hydrocarbons.
Hence, the statement 4 is correct.