1681 + Interview Questions in SOLID-STATE IN GENERAL AWARENESS Page 8 InterviewSolution

351.	`NaCl` shows Schottky defects and `AgCl` shows Frekel defects. Their electrical conductivity is due to theA. motion of ions and not the motion of electronsB. motion of electrons and not the motion of ionsC. lower coordination number of NaClD. higher coordinaiton number of AgCl
Answer» Correct Answer - A

Discussion

352.	Which of the following statements are correct in context of point defects in a crystal?A. AgCl has anion Frenkel defect and `CaF_(2)` has Schottky defectsB. AgCl has cation Frenkel defects and `CaF_(2)` has anion Frenkel defectsC. AgCl as well as `CaF_(2)` have anion Frenkel defectsD. AgCl as well as `CaF_(2)` has Schottky defects
Answer» Correct Answer - B

Discussion

353.	NaCl shows Schottky defects and AgCl Frenkel defects. Their electrical conductivity is due toA. motion of ions and not the motion of electronsB. motion of electrons and not the motion of ionsC. lower co-ordination number of NaClD. higher co-ordination number of AgCl
Answer» Correct Answer - A

Discussion

354.	Under which situtions can be amorphous substance change to crystalline form ?A. As a result of slow heating and cooling over a long period, an amorphous solid acquires some crystalline character e.g., window glass of old buildings.B.C.D.
Answer» Correct Answer - `(i) to ©, (ii) to (a), (iii) to d, (iv) to b `

Discussion

355.	Under which situations can an amorphous substance change to crystaline form?
Answer» This can be achieved by slow heating followed by cooling over a long period. For example, glass panes of windows of old buildings show this change.

Discussion

356.	A unit cell consists of a cube in which the atoms A are occupying the corners while the atoms B are present at the centre of each face. If the atoms A are missing from 2 corners, what is the simplest formuls of the compound ?
Answer» Correct Answer - `AB_(4)` Contribution by atoms A present on six corners of the unit cell = 6/8 = 3/4 Contribution made by atoms B on the centre of all the six faces = 3 The atoms of A and B are in the ratio 3/4 : 3 = 1 : 4 Formula of the compound = `AB_(4)`.

Discussion

357.	The number of atoms per unit cell in a simple cube, face `-` centred cube and body`-` centred cube are respectively `:`
Answer» Correct Answer - 2 Conceptual problem.

Discussion

358.	The unit cell of a substance has cations `A^(+)` at the corners of the unit cell and anions `B^(-)` in the centre. What is the simplest formula of the substance ?
Answer» Correct Answer - AB.

Discussion

359.	An ionic compound is made up of cations A and anions `B`. if cations `A` are at the alternate corners and anions are at the alternate faces of the cubic unit cell then empirical formula of the compound will beA. `AB_(2)`B. `A_(2)B_(3)`C. `AB_(3)`D. `AB`
Answer» Correct Answer - 1 There are `8` corners. As there are four `A` cations at the alternate corners and contribution of each `=1//8` the number of `A` cation per unit cell is `= 4xx(1)/(8)=(1)/(2)` There are `6` square faces of the cubic unit cell. but there can be only two `B` anions on alternate faces (top, bottom, and left ,right or front, rear).As contributon of each of them `=(1)/(2)` The number of `B` anions per unit cell. `=2xx(1)/(2)=1` Hence simplest ratio of cations to anions. `(A:B)` `=(1)/(2):1` or `1:2`. thus the empirical formula of the ionic compound is `AB_(2)`. There are `4` body diagonals. Since atoms within the body of the unit cell are not shared by any other unit cell there are `8` more atoms giving a total of `9`atoms.

Discussion

360.	Graphite is a good conductor of electricity due to the presence of :A. ione pair of electronsB. free valence electronsC. cationsD. amions
Answer» Correct Answer - B In graphite one carbon atom is attached to three other carbon atoms. One electron of carbon remains free. Due to this free valence electron graphite is an electrical conductor.

Discussion

361.	Graphite is a good conductor of electricity due to the presence of …….A. lone pair of electronsB. free valence electronsC. CationsD. anions
Answer» Correct Answer - C

Discussion

362.	Graphite is a good conductor of electricity due to the presence of :
Answer» Correct Answer - B Free valence electrons are responsible for the electrical conducitivity of graphite.

Discussion

363.	Calcite belongs toA. Tetragonal systemB. Trigonal systemC. Digonal systemD. Hexoagonal system
Answer» Correct Answer - B It is a fact.

Discussion

364.	Which of the following is used ot make magnetic tapes for use in audio recording?A. `CuO_(2)`B. `CoO_(2)`C. `CmO_(2)`D. `CrO_(2)`
Answer» Correct Answer - 4 `CrO_(2)`a ferromagnetic material is the oxide used to make magnetic tapes for use in audio recording.

Discussion

365.	For an ionic crystal of the formula `AX` and cooradition number `6`, the value of radius ratio will beA. greater than `0.73`B. between `0.73` and `0.41`C. between `0.41` and `0.22`D. less than `0.22`
Answer» Correct Answer - B For C.N 6, the `r^(+)//r^(-)` lies between `0.73` and `0.41`

Discussion

366.	In calcium, fluoride having the florite structures. The coordination number for calcium ion `(Ca^(2+))` and fluoride ion `(F^(-))` areA. `4` and `2`B. `6` and `6`C. `8` and `4`D. `4` and `8`
Answer» Correct Answer - 3 The `Ca^(2+)` ions are located at the face centred cubic lattice points and therefore have cubic closest packed arrangement .the `F^(-)` ions occupy all the eight tetrahedral voids.Thus the coordination number of `Ca^(2+)` ion (surrounded by eight tetrahedral voids ) is eight while the coordination number of `F^(-)` ion (occupying tetrahedral void) is four.

Discussion

367.	Density of a crystal is given by the formulaA. `(a^(3)M)/(ZN_(A))`B. `(N_(A)M)/(Za^(3))`C. `(a^(3)N_(A))/(ZM)`D. `(ZM)/(a^(3)N_(A))`
Answer» Correct Answer - D

Discussion

368.	How many energy levels are prent in `3s` conduction hand of a single crystal of sodium weighing `25.6 mg`?A. `7.01 xx 10^(20)`B. `7.01 xx 10^(23)`C. `6.02 xx 10^(23)`D. `6.68 xx 10^(20)`
Answer» Correct Answer - d `25.6 mg = (25.6)/(23)xx10^(-3)` mol `= (0.0256)/(23)N_(0)` sodium atoms Electrons in 3 s orbital in one sodium atom (conduction band) = 1. Thus total conduction bands (energy levels) `(0.0256)/(23)N_(0)` `= 6.68xx10^(20)`

Discussion

369.	Frenkel defect is caused due toA. An missing from the normal lattice site creating a vacancyB. An extra positive ion occupying an intersirttile position in the latticeC. An extra negative ion occupying an intersirttile posittion in the latticeD. The shift of a positive ion from its normal lattice site to an interstitial site
Answer» Correct Answer - d frenkel defect is due so shift of an ion form the normal lattice site (creating a vacancy ) and occupy interstitial spaces.

Discussion

370.	ZnO shows yellow colour on heating due toA. Frenkel defectB. Metal excess defectC. Metal deficiency defectD. Schottky defect.
Answer» Correct Answer - B Zinc oxide is white in colour at room temperature. On heating it loses oxygen and turns yellow. `ZnOoverset("Heating")rarrZn^(2+)+(1)/(2)O_(2)+2e^(-)` Now there is excess of zinc in the crystal and its formula becomes `Zn_(1+x)O`. The excess `Zn^(2+)` ions move to interstitial sites and the electrons to neighbouring interstitial sites.

Discussion

371.	Te defect that is more likely to occur in almost all types of ionic crystals isA. Non-stoichiometric defectsB. Schottky defect onlyC. Frenkel defectD. All the above.
Answer» Correct Answer - B Schottky defect is shown by highly ionic compounds, e.g. NaCl,KCl,KBr,AGBr,CsCl etc.

Discussion

372.	In `AgBr` crystal , the ion size lies in the order `Ag^(+) lt lt Br^(-)` The `AgHt` crystal should have the following characheristicsA. Defect less (perfect) crystalB. Schottky defect onlyC. Frenkel defect only.D. Both Schottky and Frenkel defects
Answer» Correct Answer - D In AgBr both schottky and frenkel defects occur simultaneously.

Discussion

373.	In `AgBr` crystal , the ion size lies in the order `Ag^(+) lt lt Br^(-)` The `AgHt` crystal should have the following characheristicsA. Defectless (perfect) crystalB. Schottky defect onlyC. frenkel defect onlyD. Both schotky and frenkel defects
Answer» Correct Answer - c `AgBr` exhibits Frenkel defect due to large difference in the size of `Ag^(+)` and `Br^(-)` ions.

Discussion

374.	f-centre isA. anion vacancy occupied by unpaired electronB. anion vacancy occupied by paired electronsC. anion vacancy occupied by electronD. anion present in interstitial slite
Answer» Correct Answer - A

Discussion

375.	In `AgBr` crystal , the ion size lies in the order `Ag^(+) lt lt Br^(-)` The `AgHt` crystal should have the following characheristicsA. Defectless (Perfect )crystalB. Schottky defect onlyC. Frenkel defect onlyD. Both Schottky and Frenkel defect
Answer» Correct Answer - D In AgBr both schottky and frenkel defects occur simultaneously.

Discussion

376.	A solid solution of `CdBr_(2)` in AgBr containsA. Schottky defectsB. Frenkel defectsC. Colour CentresD. Frenkel as well as Schottky defects
Answer» Correct Answer - D

Discussion

377.	The metal M crystallizes in a body centered lattice with cell edge. 400 pm. The atomic radius of M isA. 200 pmB. 100 pmC. 173 pmD. 141 pm
Answer» Correct Answer - C

Discussion

378.	The lattice site in a pur crystal cannot be occupied by ………A. moleculeB. ionC. electronD. atom
Answer» Correct Answer - D

Discussion

379.	The lattice site in a pure crystal cannot be occupied by :A. moleculeB. ionC. electonD. atom.
Answer» Correct Answer - C There are no free electrons to a pure crystal.

Discussion

380.	In an antifluorite structure, cations occupyA. octahedral voidsB. centre of the cubeC. tetrahedral voidD. corners of the cubic
Answer» Correct Answer - C In antifluorite structure anion form F.C.C structure and cation occupy all tetrahedral void

Discussion

381.	Which of the following oxides shows electrical properties like metals ?A. `SiO_(2)`B. `SO_(2)(s)`C. MgOD. `CrO_(2)`.
Answer» Correct Answer - D `CrO_(2)` shows electrical conductivity like metals.

Discussion

382.	In the primitive cubic unit cell, the atoms are present at the:A. corners of the unit cellB. centre of the unit cellC. centre of each face of the unit cellD. one set of faces of the unit cell
Answer» Correct Answer - A

Discussion

383.	which of the following oxides shows electrical properties like metals ?A. `SiO_(2)`B. `MgO`C. `SO_(2)(s)`D. `CrO_(2)`
Answer» Correct Answer - D `CrO_(2),TiO` and `ReO_(3)` are some typical metal oxides which show electrical conductivity similar to metal. While `SiO_(2),MgO` and `SO_(2)` are oxides of metal, semimetal and non-metal which do not show electrical properties.

Discussion

384.	If the atoms of an element have the radius r, then in a primitive cubic unit cell, calculate (a) the length of the face diagonal. (b) the lenth of the body diagonal.
Answer» In the Fig, AC is the face diagonal and CD is the body diagonal. ` Delta ABC` , right angled at B. ` AC = sqrt(AB^(2) +BC^(2)) = sqrt((2r)^(2) + (2r)^(2)) = sqrt(8r) = 2sqrt2 r,` In ` Delta ACD ,` right angled at A, ` CD = sqrt(AC^(2) + AD^(2)) = sqrt((2sqrt3 r)^(2) + (2r)^(2)) = sqrt(12r^(2)) = 2 sqrt3 r` ` (##PR_CHE_V01_XII_C01_E17_001_S01.png" width="80%">

Discussion

385.	which of the following oxides behaves as conductor or insulator depending upon temperature ?A. TiOB. `SiO_(2)`C. `TiO_(3)`D. MgO
Answer» Correct Answer - C Certain metal oxides like `VO_(2),VO,VO_(3) and TiO_(3)` show metallic or metallic or insulating property depending upon temperature As, temperature Varius metallic or insulating property varies this is due to vartation in energy gap between conduction band and valence band .

Discussion

386.	which of the following oxides behaves as conductor or insulator depending upon temperature ?A. TiOB. `SiO_(2)`C. `TiO_(3)`D. `MgO`
Answer» Correct Answer - C `TiO_(3)` behaves as conductor or insulator depending on temperature because of variation of energy gap between valence band and conduction bond with the variation of temperature.

Discussion

387.	A tetrahedral void in a crystal implies thatA. shape of the void is tetrahedralB. molecules forming the void are terahedral in shapeC. the void surrounded tetrahedrally by four spheresD. the void is surrounded by six spheres.
Answer» Correct Answer - C A tetrahedral void is surrounded tetrahedrally by four spheres.

Discussion

388.	In a face centred cubic lattice the number of nearest neighbours for a given lattice point are:A. 6B. 8C. 12D. 14
Answer» Correct Answer - C fcc = ccp has c . N . No. = 12

Discussion

389.	Copper crystal has a face -centred cubic lattice structure. Atomic radius of copper atom is 128 pm. Calculate the density of copper . Atomic mass of copper = 63.5 or Copper crystallises into a fcc lattice, its edge length is ` 3.62 xx 10^(-8)` cm. Calculate the dinsity of copper (atomic mass of Cu= 63.5 u, ` N_(A) = 6.022 xx 10^(23) "mol"^(-1)`)
Answer» Correct Answer - `10.71 " g cm"^(-3)` For fcc , `r= a/sqrt2 or a = 2sqrt2r = 2xx 1.414 xx 128"pm"` = 362 pm `p = (Z xx M)/(a^(3) xx N_(0)) = ( 4xx 63.5 "g mol"^(-1))/((362xx10^(-10)"cm")^(3) xx (6.02 xx 10^(23)"mol"^(-1)))= 8.9"cm"^(-3)` Alternatively, `p = ( "mass of unit cell")/("volume of unit cell") = ( 4xx(63.5 "g mol"^(-1)//6.02xx10^(23)"mol"^(-1)))/((362xx 10^(-10)"cm")^(3))= 8.9 "g cm"^(-3)`

Discussion

390.	What type of stoichiometric defect is shown by AgBr
Answer» AgBr shows both Frenkel and Schottky defects .

Discussion

391.	An example of a non- stoichiometric compound isA. `Al_(2)O_(3)`B. `NiO_(2)`C. `Fe_(3)O_(4)`D. `PbO`
Answer» Correct Answer - c `Fe_(3)O_(4)` is a non-struchumeterece compound because is it the ratio of the cations between difens from the inductted by the chemical formula.

Discussion

392.	In `A^(=)B^(-)` ionic compound radii of `A^(=) and B^(-)` ions are `180 pm ` and `187 pm` respectively .The crystal structure of this compound will beA. `NaCI` typeB. `CaCI` typeC. `ZnS` typeD. Similar to diamond
Answer» Correct Answer - b `r_(+) // r_(-) = (180)/(187) = 0.962 `which lies in the range of `0.732 - 1.000` hence coordination number `= 8 `i.e. the structure is `CaCI` type.

Discussion

393.	In `A^(+)B^(-)` ionic compound radii of `A^(=) and B^(-)` ions are `180 "pm "` and `187` pm respectively .The crystal structure of this compound will beA. NaCl typeB. CsCl typeC. ZnS typeD. similar to diamond
Answer» Correct Answer - B `r_(+)//r_(-)=(180)/(187)=0.962` which lies in the range of `0.732-1.000`, hence co-ordination number = 8 i.e. the structure is CsCl type .

Discussion

394.	A uni-univalment ionic crystal AX is composed of the following radii ( ar bitrary units) .` {:( A^(+) , X^(-)),(1.0, 2.0):}` Assuming that ions are hard spheres, predict giving reasons whether the crystal will have sodium chloride or cesium chloride structure. Calculate the volume of the unit cell.
Answer» Correct Answer - b ` r_(+)//r_(-) = 2//1 = 0.5` Which lies in the range 0.414 - 0.732 Hence, it has sodium chloride struture. ( Edge = ` 2 ( r_(+) + r_(-) = 6 "au"` . Volume =` ( 6 " au")^(3) = 216 ("au")^(3)`

Discussion

395.	The sharp melting point of crystalline solids is due to ……..A. a regular arrangement of consitituent particles observed over a short distance in the crystal lattice .B. a regular arrnagment of constituent particles observed over a long distance in the crystal lattice.C. same arrangement of consitituent particles in different direction.D. different arrangement of constituent particles in different directions.
Answer» Correct Answer - A

Discussion

396.	The coordination numbers of oxygen and silicon in `SiO_(2)` respectivelyA. 1,2B. 2,1C. 2,4D. 4,2
Answer» Correct Answer - 3

Discussion

397.	Which of the following crystallizes in fcc structrue ?A. AlB. BeC. MgD. Mo
Answer» Correct Answer - A Al crystallises in fcc structure.

Discussion

398.	The consitutent particles in carborundumA. atomsB. molecules forming the void are tetrahededral in shapeC. `+ve` ionsD. `+ve` ions in sea of electrons
Answer» Correct Answer - 2

Discussion

399.	A solid melts slightly above 273 K and is a poor conductor of heat and electricity. To which of the following categories does it belong ?A. ionic solidB. covalent solidC. metallicD. molecular.
Answer» Correct Answer - 4

Discussion

400.	What types of allignments in crystals make them ferromagnetic ?
Answer» Ferromagnetism in crystals arises due to the allignment of the unpaired electrons pointing in the same direction under the influence fo the applied magnetic field

Discussion

Explore topic-wise InterviewSolutions in .

`NaCl` shows Schottky defects and `AgCl` shows Frekel defects. Their electrical conductivity is due to theA. motion of ions and not the motion of electronsB. motion of electrons and not the motion of ionsC. lower coordination number of NaClD. higher coordinaiton number of AgCl

NaCl shows Schottky defects and AgCl Frenkel defects. Their electrical conductivity is due toA. motion of ions and not the motion of electronsB. motion of electrons and not the motion of ionsC. lower co-ordination number of NaClD. higher co-ordination number of AgCl

Under which situtions can be amorphous substance change to crystalline form ?A. As a result of slow heating and cooling over a long period, an amorphous solid acquires some crystalline character e.g., window glass of old buildings.B.C.D.

Under which situations can an amorphous substance change to crystaline form?

A unit cell consists of a cube in which the atoms A are occupying the corners while the atoms B are present at the centre of each face. If the atoms A are missing from 2 corners, what is the simplest formuls of the compound ?

The number of atoms per unit cell in a simple cube, face `-` centred cube and body`-` centred cube are respectively `:`

The unit cell of a substance has cations `A^(+)` at the corners of the unit cell and anions `B^(-)` in the centre. What is the simplest formula of the substance ?

An ionic compound is made up of cations A and anions `B`. if cations `A` are at the alternate corners and anions are at the alternate faces of the cubic unit cell then empirical formula of the compound will beA. `AB_(2)`B. `A_(2)B_(3)`C. `AB_(3)`D. `AB`

Graphite is a good conductor of electricity due to the presence of :A. ione pair of electronsB. free valence electronsC. cationsD. amions

Graphite is a good conductor of electricity due to the presence of …….A. lone pair of electronsB. free valence electronsC. CationsD. anions

Graphite is a good conductor of electricity due to the presence of :

Calcite belongs toA. Tetragonal systemB. Trigonal systemC. Digonal systemD. Hexoagonal system

Which of the following is used ot make magnetic tapes for use in audio recording?A. `CuO_(2)`B. `CoO_(2)`C. `CmO_(2)`D. `CrO_(2)`

For an ionic crystal of the formula `AX` and cooradition number `6`, the value of radius ratio will beA. greater than `0.73`B. between `0.73` and `0.41`C. between `0.41` and `0.22`D. less than `0.22`

In calcium, fluoride having the florite structures. The coordination number for calcium ion `(Ca^(2+))` and fluoride ion `(F^(-))` areA. `4` and `2`B. `6` and `6`C. `8` and `4`D. `4` and `8`

Density of a crystal is given by the formulaA. `(a^(3)M)/(ZN_(A))`B. `(N_(A)M)/(Za^(3))`C. `(a^(3)N_(A))/(ZM)`D. `(ZM)/(a^(3)N_(A))`

How many energy levels are prent in `3s` conduction hand of a single crystal of sodium weighing `25.6 mg`?A. `7.01 xx 10^(20)`B. `7.01 xx 10^(23)`C. `6.02 xx 10^(23)`D. `6.68 xx 10^(20)`

ZnO shows yellow colour on heating due toA. Frenkel defectB. Metal excess defectC. Metal deficiency defectD. Schottky defect.

Te defect that is more likely to occur in almost all types of ionic crystals isA. Non-stoichiometric defectsB. Schottky defect onlyC. Frenkel defectD. All the above.

In `AgBr` crystal , the ion size lies in the order `Ag^(+) lt lt Br^(-)` The `AgHt` crystal should have the following characheristicsA. Defect less (perfect) crystalB. Schottky defect onlyC. Frenkel defect only.D. Both Schottky and Frenkel defects

In `AgBr` crystal , the ion size lies in the order `Ag^(+) lt lt Br^(-)` The `AgHt` crystal should have the following characheristicsA. Defectless (perfect) crystalB. Schottky defect onlyC. frenkel defect onlyD. Both schotky and frenkel defects

f-centre isA. anion vacancy occupied by unpaired electronB. anion vacancy occupied by paired electronsC. anion vacancy occupied by electronD. anion present in interstitial slite

In `AgBr` crystal , the ion size lies in the order `Ag^(+) lt lt Br^(-)` The `AgHt` crystal should have the following characheristicsA. Defectless (Perfect )crystalB. Schottky defect onlyC. Frenkel defect onlyD. Both Schottky and Frenkel defect

A solid solution of `CdBr_(2)` in AgBr containsA. Schottky defectsB. Frenkel defectsC. Colour CentresD. Frenkel as well as Schottky defects

The metal M crystallizes in a body centered lattice with cell edge. 400 pm. The atomic radius of M isA. 200 pmB. 100 pmC. 173 pmD. 141 pm

The lattice site in a pur crystal cannot be occupied by ………A. moleculeB. ionC. electronD. atom

The lattice site in a pure crystal cannot be occupied by :A. moleculeB. ionC. electonD. atom.

In an antifluorite structure, cations occupyA. octahedral voidsB. centre of the cubeC. tetrahedral voidD. corners of the cubic

Which of the following oxides shows electrical properties like metals ?A. `SiO_(2)`B. `SO_(2)(s)`C. MgOD. `CrO_(2)`.

In the primitive cubic unit cell, the atoms are present at the:A. corners of the unit cellB. centre of the unit cellC. centre of each face of the unit cellD. one set of faces of the unit cell

which of the following oxides shows electrical properties like metals ?A. `SiO_(2)`B. `MgO`C. `SO_(2)(s)`D. `CrO_(2)`

If the atoms of an element have the radius r, then in a primitive cubic unit cell, calculate (a) the length of the face diagonal. (b) the lenth of the body diagonal.

which of the following oxides behaves as conductor or insulator depending upon temperature ?A. TiOB. `SiO_(2)`C. `TiO_(3)`D. MgO

which of the following oxides behaves as conductor or insulator depending upon temperature ?A. TiOB. `SiO_(2)`C. `TiO_(3)`D. `MgO`

A tetrahedral void in a crystal implies thatA. shape of the void is tetrahedralB. molecules forming the void are terahedral in shapeC. the void surrounded tetrahedrally by four spheresD. the void is surrounded by six spheres.

In a face centred cubic lattice the number of nearest neighbours for a given lattice point are:A. 6B. 8C. 12D. 14

What type of stoichiometric defect is shown by AgBr

An example of a non- stoichiometric compound isA. `Al_(2)O_(3)`B. `NiO_(2)`C. `Fe_(3)O_(4)`D. `PbO`

In `A^(=)B^(-)` ionic compound radii of `A^(=) and B^(-)` ions are `180 pm ` and `187 pm` respectively .The crystal structure of this compound will beA. `NaCI` typeB. `CaCI` typeC. `ZnS` typeD. Similar to diamond

In `A^(+)B^(-)` ionic compound radii of `A^(=) and B^(-)` ions are `180 "pm "` and `187` pm respectively .The crystal structure of this compound will beA. NaCl typeB. CsCl typeC. ZnS typeD. similar to diamond

A uni-univalment ionic crystal AX is composed of the following radii ( ar bitrary units) .` {:( A^(+) , X^(-)),(1.0, 2.0):}` Assuming that ions are hard spheres, predict giving reasons whether the crystal will have sodium chloride or cesium chloride structure. Calculate the volume of the unit cell.

The coordination numbers of oxygen and silicon in `SiO_(2)` respectivelyA. 1,2B. 2,1C. 2,4D. 4,2

Which of the following crystallizes in fcc structrue ?A. AlB. BeC. MgD. Mo

The consitutent particles in carborundumA. atomsB. molecules forming the void are tetrahededral in shapeC. `+ve` ionsD. `+ve` ions in sea of electrons

A solid melts slightly above 273 K and is a poor conductor of heat and electricity. To which of the following categories does it belong ?A. ionic solidB. covalent solidC. metallicD. molecular.

What types of allignments in crystals make them ferromagnetic ?