Chemistry

Solid State and Crystal Structures

198 Questions

Solid state chemistry focuses on the structural properties of crystalline solids. Questions cover Bravais lattices, unit cells, and close packed structures. This topic is essential for chemistry papers in UPSC and state PSC examinations.

Bravais lattice typesUnit cell calculationsClose packed structuresCrystal densityBragg's LawWurtzite structure

Solid State and Crystal Structures Questions

Multiple choice

Which of the following combinations of ‘limiting radius ratio: coordination number- shape’ is not correctly matched?

  1. < 0.155 : 2- linear

  2. 0.155 - 0.225 : 3- triangular planar

  3. 0.225 – 0.414 : 4- tetrahedral

  4. 0.414 – 0.732 : 4- square planar

  5. 0.732 – 0.999 : 6- octahedral
Reveal answer Fill a bubble to check yourself
E Correct answer
Explanation

For coordination number 6 the shape is octahedral with limiting radius ratio of 0.414 – 0.732. The radius ratio 0.732 – 0.999 is limiting for coordination number 8 with cubic shape.

Multiple choice

Which of the following sets of ‘crystal system type: number of space lattices - lattice type’ is not correctly matched?

  1. Cubic: 3 - face centred cubic

  2. Orthorhombic: 2 - body centred rectangular prism

  3. Tetragonal: 2 - body centred tetragonal prism

  4. Monoclinic: 2 - face centred parallelepiped

  5. Triclinic: 1 - triclinic parallelopiped
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Orthorhombic crystals have four space lattices with body centred rectangular prism arrangement.

Multiple choice

If the distance between Na+ and Cl- ions in face centred cubic NaCl crystal is 265 pm, then what will be the apparent radius of NaCl crystal?

  1. 125.5 pm

  2. 128.3 pm

  3. 160.6 pm

  4. 187.35 pm

  5. 530 pm
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Edge length of the NaCl crystal = 2 x distance between Na+ and Cl- ions = 2 x 265 = 530 pm Now, for face centred cubic unit cell, a√2 = 4r r = a√2 / 4 = 530 x 1.414/4 = 187.35 pm. Hence, the apparent radius of NaCl crystal is 187.35 pm.

Multiple choice

The crystal structure of austenite is

  1. body centered cubic

  2. face centered cubic

  3. hexagonal closed packed

  4. body centered tetragonal
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Austenite is a solid solution of carbon in $\gamma - iron$. It has a solid solubility of upto 2% C at $1130^0C$

Multiple choice

If three elements M, N and O are crystallized in cubic solid lattice with M atoms at corners, N atoms at cube centre & O atoms at the edges, then the formula of the compound is

  1. MNO

  2. MN3O

  3. MNO3

  4. M3NO
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Atom M is shared by 8 corners; 1 atom of O is shared by 4 unit cells. Atom N is present at centre of the unit cell. Hence, the effective number of atoms of M per unit cell = 8 X 1/8 = 1. The effective number of atoms of O per unit cell = 12/4 = 3.The effective number of atoms of N per unit cell = 1. Hence, the formula of the compound is MNO3.

Multiple choice chemistry solid state imperfections in solids

The incorrect statement is :

  1. When crystals of NaCI are heated in an atmosphere of sodium vapour, it appears yellow due to F-centres.
  2. $ O _2 $ is paramagnetic , $ CrO _2 $ is Ferromagnetic and $ MnO $ is anti-Ferromagnetic
  3. Certain oxides $ VO, VO _2VO _3 $ and $ TiO _3 $ show metallic properties at all temperatures.

  4. CCP & HCP have same coordination number.
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The statement regarding VO, VO2, VO3, and TiO3 is incorrect because these oxides show metallic or insulating properties depending on the temperature, rather than metallic properties at all temperatures. The other statements correctly describe F-centres, magnetic properties, and close-packing structures.

Multiple choice chemistry solid state imperfections in solids

The presence of excess sodium in sodium chloride makes the crystal appearance yellow. This is due to the presence of

  1. Schottky defect

  2. Frenkel defect

  3. F-centres

  4. Interstitial defects
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

When NaCl crystals are heated in sodium vapor, sodium atoms deposit on the surface and chloride ions diffuse to the surface to form NaCl. The remaining electrons occupy the anionic vacancies, creating F-centres, which absorb light and impart a yellow color.

Multiple choice chemistry solid state imperfections in solids

In feldspar and zeolite, $Si^{4+}$ ions are replaced by which ions?

  1. Oxide ion

  2. Hydroxide ion

  3. Aluminium ion

  4. Potassium ion
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Generally, the ion exchange tendency of a material depends on the extent of isomorphous substitution in the tetrahedral framework. Thus, the $Si^{4+}$ ions of feldspar and zeolite are replaced by $Al^{3+}$ (aluminium ion).

Multiple choice chemistry solid state imperfections in solids

ZnO shows yellow colour on Heating due to:

  1. d-d transition

  2. C-T spectra
  3. Higher polarisation caused by $Zn^{2+}$ ion

  4. F-centres
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

$ZnO$ shows yellow colour of heating due to F-centre

$ZnO\longrightarrow Zn^{2+}+2e^-+\cfrac{1}{2}O _2$
Electron get trapped in anion sites. This is called as F-centre. Due to F-centre colour of many compounds occurs.

Multiple choice chemistry d and f block elements imperfections in solids solid solutions formation of complex compounds and constituent of catalysts general characteristics of first transition series

Which of the following is an interstital compound ?

  1. $ PdCI _2 $
  2. $ NH _3 $
  3. $ ZnO$
  4. $ TiH $
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Interstitial compounds are formed when small atoms like hydrogen, carbon, or nitrogen are trapped in the crystal lattices of transition metals. Titanium hydride (TiH) is a classic example of a non-stoichiometric interstitial hydride.

Multiple choice redox and stoichiometry applications of redox reaction oxidation- reduction reactions redox reactions chemistry

In a solid $AB$ of $NaCl$ structure, A atoms occupy the corners of the cubic unit cell. If all the corner atoms are removed then the formula of the unit cell will be

  1. $A _{4}B _{4}$
  2. $B$
  3. $A _{3}B _{4}$
  4. $AB$
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

In an NaCl structure, A atoms are at corners and face centers (total 4). If all corner atoms (8 corners * 1/8 = 1 atom) are removed, 3 A atoms remain. B atoms are at edge centers and body center (total 4). The formula becomes A3B4.