SOLID-STATE-QUIZ-12

Solid State Quiz-12

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. The crystalline structure of NaCl is

•  Hexagonal close packing
•  Face centred cubic
•  Square planar
•  Body centred cubic

Solution
Sodium chloride (NaCl) has face centred cubic structure. It contains 4and 4in the unit cell. Eachis surrounded by 6ions and vice−versa. 

Q2.An element has bcc structure having unit cells . The number of atoms in these cells is :

•  
•  
•  
•  

Solution
One unit cell of bcc has atoms = 2.

Q3.  How many octahedral and tetrahedral holes are present per unit cell in a face centred cubic

arrangement of atoms?

•   8, 4
•  1, 2
•  4, 8
•  2, 1

Solution
In fcc octahedral voids : at the centre = 1 

                                        at the edges =12 ×1/4=3

                  ∴ Total =4

In fcc tetrahedral voids : 8

Q4. The metal surfaces are excellent reflectors because of absorption and re-emission of light by :

•  Protons in atom
•  Electrons in atom
•  Neutrons in atom
•  None of these

Solution
The presence of free electrons in metals, they are opaque, strongly reflecting and possess metallic lustre.

Q5.Solid CO2 is an example of :

•  Molecular crystal
•  Covalent crystal
•  Metallic crystal
•  Ionic crystal

Solution
 Molecular solids are the substances having molecules as constituent units having interparticle forces such as van der waal’s forces or hydrogen bonds.

Q6. Coordination number of Zn in ZnS (zinc blende) is

•  6
•  4
• 8
•  12

Solution
In ZnS each sulphide ion is tetrahedrally surrounded by four zinc ions and each zinc ion is surrounded by four sulphide ions. Thus, zinc sulphide possesses 4 : 4 coordination.

Q7.The phenomenon in which polar crystals on heating produce electricity is called :

•  Pyro-electricity
•  Piezo-electricity
•  Ferro-electricity
•  Ferri-electricity

Solution
It is the definition of pyro-electricity.

Q8.Lubricating properties of graphite are diminished in presence of :

•  High pressure
•  Low pressure
•  Vacuum
•  None of these

Solution
In vacuum, there is no friction.

Q9.The axial angles in triclinic crystal system are

•  α=β=γ=90°
•  α=γ=90°, β≠90°
•  α≠β≠γ≠90°
•  α=β=γ≠90°

Solution
The axial angles in triclinic crystal system are different and none is perpendicular to any of the others i.e., α≠β≠γ≠90°.

Q10. NaCl structure consists of :

•  Na and Cl atoms
• and Cl atoms
•  Na atoms andion
• andions

Solution
NaCl hasandions in solid state.