Solid State Quiz-9
Dear Readers,
The one subject in NEET which is candidates who can easily attain good marks is Chemistry. That's the reason, often, one doesn’t pay notice and choose to compromise it. But if one wants to rank above others, the tip is to be thorough with NEET chemistry concepts. The understanding of reactions and definite basic understanding is what requires major attention in Chemistry but once done it only gets simpler from there. The main focus on the to-do list should be on getting a hang of the NCERT syllabus of NEET chemistry..
Q1. Density of a crystal remains unchanged as a result of
Solution
Due to Frenkel defect, density of a crystal remains unchanged.
Due to Frenkel defect, density of a crystal remains unchanged.
Q2.Number of atoms in the unit cell of Na(bcc type crystal) and Mg(fcc type crystal ) are respectively
Solution
Number of atoms in unit cell of Na are 2 (bcc).
Number of atoms in unit cell of Na are 2 (bcc).
Number of atoms in unit cell of Mg (fcc) are 4.
Q3. The unit cell cube length for LiCl (just like NaCl structure) is 5.14 Å , Assuming
anion-anion contact, the ionic radius for chloride ion is:
Solution
The distance between Li+ and Cl− ion can be derived as half of the edge length of cube.
The distance between Li+ and Cl− ion can be derived as half of the edge length of cube.
Q4. Silicon dioxide is an example of :
Solution
is covalent crystal like diamond and graphite.
Q5.In which of the following crystals alternate tetrahedral voids are occupied?
- NaCl
- Zns
-
-
Solution
In ZnS structure, sulphide ions occupy all (fcc) lattice points while Zn2+ ions are present in alternate tetrahedral sites. Therefore, there is one Zn2+ ion for every S2− ion.
In ZnS structure, sulphide ions occupy all (fcc) lattice points while Zn2+ ions are present in alternate tetrahedral sites. Therefore, there is one Zn2+ ion for every S2− ion.
Q6. If the positions of Na+ and Cl− are interchanges in NaCl, the crystal lattice with respect to
Na+ and Cl− is :
Solution
Each Na+ (in bcc) in NaCl is surrounded by six Cl− (in fcc) and each Cl− in NaCl is surrounded by six Na+ and thus, on interchanging Na+ and Cl− the fcc structure of NaCl will not change but with respect to Na+ it will be fcc and with respect to Cl− it will be bcc.
Each Na+ (in bcc) in NaCl is surrounded by six Cl− (in fcc) and each Cl− in NaCl is surrounded by six Na+ and thus, on interchanging Na+ and Cl− the fcc structure of NaCl will not change but with respect to Na+ it will be fcc and with respect to Cl− it will be bcc.
Q7.A solid AB has NaCl type structure with edge length 580.4 pm. The radius of A+ is 100 pm.
What is the radius of
B− ?
Solution
NaCl has fcc structure and thus,
NaCl has fcc structure and thus,
Q8.Sodium metal crystallises at room temperature in a body centred cubic lattice with a cell edge
a=4.29 Å. The radius of sodium atom is
Solution
For a body centred cubic lattice radius, (r)
For a body centred cubic lattice radius, (r)
Therefore, radius of 
Q9.The elements commonly used for making transistors are
Solution
Si and Ge are used for making transistors.
Si and Ge are used for making transistors.
Q10. Most crystals show good cleavage because their atoms, ions and molecules are:
Solution
Due to different plane arrangement, cleavage becomes easier at these points.
Due to different plane arrangement, cleavage becomes easier at these points.
