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InterviewSolution
This section includes InterviewSolutions, each offering curated multiple-choice questions to sharpen your knowledge and support exam preparation. Choose a topic below to get started.
| 251. |
Potassium dichromatic, blue vitriol, and boric acid all crystal-lize in theA. cubic ( or regular) systemB. orthorhomic ( or rhombic) systemC. rhombohedral ( or trigonal) systemD. triclinic (or anorthitic) system |
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Answer» Correct Answer - 4 They are crystallize in the triclinic system `:a!=b!=c` and `alpha!=beta!=gamma!=90^(@)` .Other examples are `CuF_(2)` and `NaHSO_(4)`. |
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| 252. |
In the crystal lattice of diamond carbon atoms adoptA. fcc arrangement along with occupancy of `50%` lertabedral holesB. fcc arrangement along with occupancy of `25%` lertabedral holesC. fcc arrangement along with occupancy of `25%` octabedral holesD. bcc arrangement |
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Answer» Correct Answer - a Only two terahedral holes are occupied dimond |
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| 253. |
A binary solid`(A^(+) B^(-))` has a zinc blende stracture with B ions constituting the lattice and `A^(+)` inos occupying `25%` of the terahedral holes. The formula of the solid isA. `AB`B. `A_(2)B`C. `AB_(2)`D. `AB_(4)` |
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Answer» Correct Answer - c Suppose the number of `H` inos that consitute the lattice is `100` The number of trtrahedral sites `= 200` |
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| 254. |
In orthorhombic , the value of a, b and c are respectively `4.2Å, 8.6 Å and 8.3Å` .Given the molecular mass of the solur is `155 gm mol^(-1)` and that of density is `3.3 gm//cc` the number of formula unit per unit cell isA. 2B. 3C. 4D. 6 |
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Answer» Correct Answer - C `Z=(VxxN_(0)xxd)/(M)` `=(4.2xx8.6xx8.3xx10^(-24)xx6.023xx10^(23)xx3.3)/(155)=3.84=4` |
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| 255. |
In orthorhombic , the value of a, b and c are respectively `4.2Å, 8.6 Å and 8.3Å` .Given the molecular mass of the solur is `155 gm mol^(-1)` and that of density is `3.3 gm//cc` the number of formula unit per unit cell isA. `2`B. `3`C. `4`D. `6` |
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Answer» Correct Answer - c `Z= (Y xx N_(0) xx d)/(M)` `= (4.2 xx 8.6 xx 5.3 xx 10^(-24) xx 6.025 xx 10^(25) xx 3.3)/(155)` `= 3.84 = 4` |
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| 256. |
Schottky defect defines imperfection in the lattice structure of aA. SolidB. LiquidC. GasD. Plasma |
| Answer» Correct Answer - A | |
| 257. |
In the crystals of which of the following ionic compounds would you expect maximum distance between the centres of the cations and anion?A. LiFB. CsFC. CsID. LiI |
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Answer» Correct Answer - C The distance is maximum in the centres of `Cs^(+)` and `I^(-)` ions. |
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| 258. |
If we mix a pentavalent impurity in the crystal lattice of germinium the type of semiconductor formed will be:A. p-typeB. n-typeC. both (a) and (b)D. None of the two |
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Answer» Correct Answer - B n-type semiconductor will be formed due to the availability of free electrons |
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| 259. |
If we mix a pentavalent impurity in the crystal lattice of germinium the type of semiconductor formed will be:A. p-typeB. n-typeC. Both a and bD. None of these |
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Answer» Correct Answer - B On adding a pentavalent impurity with germanium we get, n-type of semiconductors because excess of electrons is responsible for conduction . |
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| 260. |
The corrent statement regarding defects is solids in solids isA. Frenkel defect is usually favoured by a very small difference in the sizes of cation and anion.B. Frenkel defect is a dislocation defectC. Trapping of an electron in the lattice leads to the formation of F-centerD. Schottky defects have no effect on the physical properties of solids. |
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Answer» Correct Answer - B::C Frenkel defect is a dislocation defect. Trapping of an electron in the lattice leads to the formation of F-center. |
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| 261. |
The corrent statement regarding F-centre isA. Electron are held in the voids of crystalsB. F-centre produces colour to the crystals.C. Conductivity of the crystal increases due to F-centreD. All |
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Answer» Correct Answer - D All the given statements are correct about F-centres. |
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| 262. |
In an insulator, the forbidden energy gap between the valence band and conduction band is of the order ofA. Both the bands are overlapped with each otherB. Very smallC. InfiniteD. Very large. |
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Answer» Correct Answer - D When insulators (non metal atoms) interact to form a solid, their atomic orbitals mix to form two bunch of orbitals, separated by a large hand gap. Electrons cannot therefore be promoted to an empty level, where they could move freely. |
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| 263. |
Insulators are the solid with very low conductivities ranging between A… Here , A refers toA. `10^4 "to " 10^7 Omega^(-1) m^(-1)`B. `10^(-20) " to " 10^(-5) Omega^(-1) m^(-1)`C. `10^(-20) " to " 10^(-10) Omega^(-1) m^(-1)`D. 10^(-6) " to " 10^4 Omega^(-1) m^(-1)` |
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Answer» Correct Answer - C Insulators are the solids with very low conductivities , ranging between `10^(-20) " to " 10^(-10) Omega^(-1) m^(-1)` |
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| 264. |
Which of the following is not correct for ionic crystalsA. They possess high melting point and boiling pointB. All are electrolyteC. Exhibit the property of isomorphismD. Exhibit directional properties of the bond |
| Answer» Correct Answer - D | |
| 265. |
which of the following is true about the change the charge acquired by p- type semiconductors ?A. positiveB. neutralC. negativeD. depends on concentration of p impurity |
| Answer» Correct Answer - A | |
| 266. |
Experimentally it was found that a metal oxide has formula `M_(0.98)O`. Metal M, present as `M^(2+) and M^(3+)` in its oxide. Fraction of the metal which exists as `M^(3+)` would beA. `5.08%`B. `7.01%`C. `4.08%`D. `6.05%` |
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Answer» Correct Answer - C The formula `M_(0.98)O` Shows that if there are 100 O-atoms present as `O^(2-)` ions then there are 98 M atoms present as `M^(2+)` and `M^(3+)` . Suppose `M^(3+)=x` then `M^(2+)=98-x`. As the compoumd as a whole in neutral. Total charge on `M^(3+)` and `M^(2+)=` total charge on `100O^(2-)` ions `x(+3)+(98-x)(+2)=100xx2` `3x+196-2x=200` or x=4 `:.` % of `M^(3+)=(4)/(98)xx100=4.08%` |
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| 267. |
Experimentally it was found that a metal oxide in formula `M_(0.98)O`. Metal `M` is present as `M^(2+)` and `M^(3+)` in its oxide ,Fraction of the metal which exists as `M^(3+)` would beA. `7.01%`B. `4.08%`C. `6.05%`D. `5.08%` |
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Answer» Correct Answer - B |
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| 268. |
Pure silicon and germanimum areA. ConductorsB. InsulatorsC. SemiconductorsD. May be any one of the above |
| Answer» Correct Answer - B | |
| 269. |
Density of Li atom is ` 0.53 " g/cm"^(3)`, the edge length of Li is 3.5 Å . Find out the number of Li atoms in a unit cell ` ( N_(0) = 6.023 xx 10^(23) , M = 6.94) |
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Answer» The aim is to find Z in the formula ` p = ( Z xx M)/ (a^(3) xx N_(0)) ` ` Z= ( p xx a^(3) xx N_(0)) /M = ( 0.53 g cm ^(-3) xx ( 3.5 xx 10^(-8) cm)^(3) xx ( 6.023 xx 10^(3) mol^(-1)))/(6.94 " g mol"^(-1)) = 1.97 = 2 ` |
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| 270. |
Why is coordination number of 12 not found in lonic crystals ? |
| Answer» maximum radius in ionic crystals lies in the range 0.732 -1 which correspondes to a corrdination number of 8. Hence , coordination number greater than 8 is not possible in ionci crystals. | |
| 271. |
An element crystallize in f.c. lattice with cell edge of 250 pm. Calculate the density if 300 g of this element contains ` 2 xx 10^(24) ` atoms. |
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Answer» Correct Answer - ` a = 5.94 xx 10^(-8) cm , V = a^(3) = 2.096 xx 10^(-22) cm^(3) ` Molar mass of the emlment (M) = `( 300)/(2xx 10^(24)) xx 6.02xx 10^(23) = 90.3 " g mol"^(-1)` Density `(p)= (Z xx M)/(a^(3)xxN_(0))= (4xx90.3)/((250xx10^(-10))^(3) xx (6.02 xx 10^(23))) = 38.4 " g mol" ^(-3)` |
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| 272. |
The ions of NaF and MgO all have the same number of electrons and internuclear distances are about the same (235 pm and 215 pm). Why are then the melting points of NaF and MgO so different `(992^(@) C and 2642^(@)C)` ? |
| Answer» In ` Mg^(2+)O^(2-)` , both ions carry two units of charge whereas in ` Na^(+) F^(-)` , each ions carries only one unit charge. Hence, eelctrostatic forces of attraction in MgO are stronger. | |
| 273. |
Thallium chloride (TICI) crystallizes in a cubic lattice whose edge length is found to be 385 pm. If the density of the solid is found to be ` 7.0 " g cm"^(-3)` , predict the type of lattice to which the crystals of TICI belong . (Atomic mass of TI = 204, Cl = 35.5) |
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Answer» Correct Answer - Z = 4, i.e, ` 4 Fe^(2+) and O^(2-) ` ion Calculate Z. It comes out to be 1. This shows that a unit cell TICI has one formula unit if TICI. Hence .it has body - centred cubic lattic (similar tot hat if CsCl) |
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| 274. |
Diamond and solid rhomibc suplhur both are covalnet solids but the latter has very low melting point than the former. Explain why . |
| Answer» Diamond is three dimesional net work covalent solid with strong interatomic forces whereas sulphur is a molecular solid consisting of puckered eight membered rings `(S_(8))` held together by weak van der waals forces. | |
| 275. |
Use the data given below the find the type of cubic lattice to which the crystal of iron belongs : a/pm= 286, p/g ` "cm"^(-3) = 7.86` |
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Answer» Correct Answer - BCC Calculate Z( Z =2 means BCC) |
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| 276. |
which of the following is true about the value of refractive index of quartz glass ?A. Same in all directionsB. Different in different directionsC. Cannot be measuredD. Always zero. |
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Answer» Correct Answer - A Quartz glass has the same refractive index in all the directions since it is an amorphous solid. |
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| 277. |
which of the following is true about the value of refractive index of quartz glass ?A. same in all directionsB. Different in difference directionC. Cannot be measuredD. Always zero |
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Answer» Correct Answer - A Since quartz glass is an amorphous solid having short range order of constistutents. Hence, value of refractive index is same in all directions, can be measured and not be equal to zero always. |
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| 278. |
Column -A (a) Glass (B) Quartz (C) Metallic crystal Column -B (1) Framework silicate (2) Melleable & ductile (2)Pseudo solid The correct match inA. `{:(A,B,C),(1,3,2):}`B. `{:(A,B,C),(3,1,2):}`C. `{:(A,B,C),(2,1,3):}`D. `{:(A,B,C),(1,2,3):}` |
| Answer» Correct Answer - 2 | |
| 279. |
which of the following is true about the value of refractive index of quartz glass ?A. Same in all directionsB. Different in different directionsC. Cannot be measuredD. Always zero |
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Answer» Correct Answer - A since , quartz is an amorphous solid having range of constiuents . Hence ,value of refraactive index is same in all directions can measures and not be equal to zero always . |
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| 280. |
Silica `(SiO_(2))` can be crystalline as well as amorphes with following properties (I) it has hight and sharp melting point (II) Crystalline (III) The `SiO_(4)^(2)` letrahedral are randomly joined to give polymeric chains or three - demensional sheets Which of the properties is/are matced with amophous solids?A. IB. IIIC. I,IIID. II |
| Answer» Correct Answer - 3 | |
| 281. |
Calculate the density of flourine nucleus supposing that the shape of the nucleus is spherical and its radius is `5 xx 10^(-13)`. (Mass of `F`=`19` amu)A. `6.02xx10^(3) g " cm"^(-3)`B. `5xx10^(4) g " cm"^(-3)`C. `6.02xx10^(3) g " cm"^(-3)`D. `5xx10^(13) g " cm"^(-3)` |
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Answer» Correct Answer - C Radius of nucleus of F atom `=5xx10^(-13) " cm"` Volume of sphere `=4//3pir^(3)=4//3xx22//7(5xx10^(-13)" cm")^(3)` Mass of `6.023xx10^(23)` atoms of F (or their nuclei)=19g Mass a 1 atom or 1 nucleus `=19//6.023xx10^(23)g` Density of matter in F nucleus `=("Mass of nucleus")/("Volume of nucleus")` `=((19g)xx3xx7)/((6.023xx10^(23))xx4xx22xx(5xx10^(-13)" cm")^(3))` `=6.02xx10^(13)g " cm"^(-3)` |
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| 282. |
Which of the folloiwng statement for cyrstals having Schottly defect is not correct?A. Schottky defect arises due to the absence of a cation and anion from the position which it is expected to occupyB. schooty defect ar emore commmon in ionic compound with high co-ordination numberC. The dinsity of the crystals having schottky defect is larger than that of the perfect crystalD. The crystal having schottly defect is electrically neutral as a whole. |
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Answer» Correct Answer - C |
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| 283. |
Explain similarities between metallic and ionic crystals . |
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Answer» Similarities between ionic and metallic crystals : `to` Both ionic and metallic crystals have electrostatic force of attraction . `to` The bond present in ionic crystals and metallic crystals is non-directional . |
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| 284. |
Which of the following is a three dimensional silicateA. MicaB. SpodumeneC. ZeoliteD. None of these |
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Answer» Correct Answer - C radius ratio range 0.732-0.99 signifies co-ordination number 8. In CsCl, co-ordination number ratio is 8:8 |
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| 285. |
Give an example of ageometrical figure which has neither a line of symmetry nor a rotationalsymmetry.A. HexagonalB. Orthorhombic IC. CubicD. Triclinic. |
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Answer» Correct Answer - D In a triclinic crystal has no rotation of symmetry. |
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| 286. |
If the radius of `Na^(+)` ion is `95 p m` and that of `Cl^(-)` ion is `181 p m`, then `:`A. co-ordination no. Of `Na^(+)` is 6B. co-ordination no. Of `Cl^(-)` is 8C. length of the unit cell is 552 "pm"D. length of the unit cell is 380"pm" |
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Answer» Correct Answer - A::C |
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| 287. |
Position of octahedral voids in fcc structure is//areA. edge centersB. face centersC. body centersD. corners |
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Answer» Correct Answer - A::C |
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| 288. |
Position of octahedral voids in fcc structure is//areA. Edge centre of unit cellB. Body centre of unit cellC. Corners of unit cellD. Face centre of unit cell |
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Answer» Correct Answer - A::B `OVs` are present at edge centre and body centre in an fcc unit cell. |
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| 289. |
Which of the following statements is/are correct about `TVs` in an fcc unit cell?A. Number of `TVs` per atom in fcc unit cell is `2`.B. Number of `TVs` per unit cell is `8`.C. Number of `TVs` is twice the number of atoms in the fcc unit cell.D. Number of `TVs` is equal to the number of atoms in the fcc unit cell? |
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Answer» Correct Answer - A::B::C Refer Section 1.14.4, Figs. 1.52(d) and 1.52(e). |
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| 290. |
Position of `TVs` in closest packed structure is//areA. Edge centre of unit cellB. Two `TVs` on each body diagonalC. Position of each `TV` from corner is `sqrt(3)a//4`.D. Face centre of unit cell |
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Answer» Correct Answer - B::C Two `TVs` present on each body diagonal of fcc unit cell at a distance of `sqrt(3)a//4` from each corner. (Refer section 1.14.4, Figs. 1.52(d) and 1.52(e). |
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| 291. |
The ratio of closed packed atoms to tetrahedral holes in cubic close packing is `:`A. `1:1`B. `1:2`C. `1:3`D. `2:1` |
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Answer» Correct Answer - B Every constituent has two tetrahedral voids in ccp lattice atoms `=8xx(1)/(8)+6xx(1)/(2)=4` `therefore` Tetrahedral void `=4xx2=8`, thus ratio `=4:8::1:2`. |
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| 292. |
Antifluorite structure is derived from fluorite structure by:A. NaFB. `SrF_(2)`C. `AlCl_(3)`D. `SiF_(4)` |
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Answer» Correct Answer - B `SrF_(2)` has fluorite `(CaF_(2))` type structure. |
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| 293. |
Which of the follwing statements is/are correct for both fluorite and antifluorite structures?A. Cation is present in alternate `TV_(s)`B. Anion constitutes lattice.C. Number of formula unit in one unit cell is `4`.D. `100%` tetrahedral voids are occupied |
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Answer» Correct Answer - C::D In both fluoruite and antifluorite, `100% TVs` are occupied and `Z_(eff)` (number of formula unit) for both is `4`. |
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| 294. |
Close packing is maximum in the crystal lattice of :A. NaClB. MgC. AlD. None of these |
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Answer» Correct Answer - B Co-ordiantion number in hcp=12 Co-ordination number in Mg is also=12. |
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| 295. |
In antifluorite structure, `50%` of `TVs` are occupied by anion. |
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Answer» Correct Answer - F Cation occupies all `TVs`(i.e., `100% TVs`). |
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| 296. |
There are four formula units in fluorite and antifluorite structure. |
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Answer» Correct Answer - T Both have `Z_(eff) = 4`. In flourite-type formula is `A_(4)B_(8) = 4AB_(2)`, but in anitfluorite-type formula is `A_(8)B_(4) = 4A_(2)B`. |
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| 297. |
Antifluorite structure is for `:`A. Octahedral voidsB. Centre of cubeC. Tetrahedral voidsD. Corners of cube. |
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Answer» Correct Answer - C In antifluorite structure the oxide ions (Anions) form a face-centered cubic array and the metal ions (cations) fill half the tetrahedral voids. Example. `Na_(2)O` |
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| 298. |
A solid is made of two element `X` and `Y` .The atoms `Z` are in `C CP` arrangement while the atoms `X` occupy all the terahedral sites .What is the formula of the compound ?A. `XZ`B. `XZ_(2)`C. `X_(2)Z`D. `X_(2)Z_(3)` |
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Answer» Correct Answer - c Tetrahedral atoms are twice as compacred is octabedral siles then the into of `X` and` Z` is `2 :1` Hence formula of the compound `X_(2)Z`. |
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| 299. |
A solid is made of two element `X` and `Y` .The atoms `Z` are in `C CP` arrangement while the atoms `X` occupy all the terahedral sites .What is the formula of the compound ?A. XZB. `XZ_(2)`C. `X_(2)Z`D. `X_(2)Z_(3)` |
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Answer» Correct Answer - C Tetrahedral sites one double comparable to octahedral sites then ratio of X and Z respectively 2:1 since formula of the compound `X_(2)Z`. |
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| 300. |
A solid is made of two element `X` and `Y` .The atoms `Z` are in `C CP` arrangement while the atoms `X` occupy all the terahedral sites .What is the formula of the compound ?A. `PO_(2)`B. `P_(2)O`C. `PO`D. `P_(2)O_(2)` |
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Answer» Correct Answer - a Four atoms `(P)` contribute in one unit cell from ccp arrangement and `4` atoms `(Q)` from the all stratetral void contributes one unit cell So, formula of solid ids` P_(4)Q_(8)` so , the simples formulas of the solid is `PQ_(3)` |
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