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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.
| 901. |
The regular three dimensional arrangement of points in a crystal is known as crystal lattice and the smallest repeating pattern in the lattice is called unit cell. The unit cells are characterised by the edge lengths a, b, c and the angles between them `alpha, beta and gamma` respectively. Based on this, there are seven crystal systems. In a cubic unit cell: `a=b=c and alpha = beta=gamma=90^(@)` The number of points in simple, body centred and face centred cubic cells are 1,2 and 4 respectively In both the hcp and ccp of spheres, the number of tetrahedral voids per sphere is two while the octahedral voids is one. A double triangular void surrounded by three spheres above and three spheres below is calledA. triangular voidB. tetrahedral voidC. octahedral voidD. trigonal bipyramidal void |
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Answer» Correct Answer - C Void is octahedral in nature |
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| 902. |
The regular three dimensional arrangement of points in a crystal is known as crystal lattice and the smallest repeating pattern in the lattice is called unit cell. The unit cells are characterised by the edge lengths a, b, c and the angles between them `alpha, beta and gamma` respectively. Based on this, there are seven crystal systems. In a cubic unit cell: `a=b=c and alpha = beta=gamma=90^(@)` The number of points in simple, body centred and face centred cubic cells are 1,2 and 4 respectively In both the hcp and ccp of spheres, the number of tetrahedral voids per sphere is two while the octahedral voids is one. In a face centred cubic cell, an atom at the face contributes to the unit cellA. 1 partB. `1//2` partC. `1//4` partD. `1//8` part |
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Answer» Correct Answer - B In fcc unit cell, an atom at the face centre is in contact with two unit cells. It contribution to the unit cell `=1//2` |
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| 903. |
The smallest repeating pattern which when repeated in three dimensions results in the crystal of the substance is calledA. space latticeB. crystal latticeC. unit cellD. coordination number |
| Answer» Correct Answer - C | |
| 904. |
The regular three dimensional arrangement of points in a crystal is known as crystal lattice and the smallest repeating pattern in the lattice is called unit cell. The unit cells are characterised by the edge lengths a, b, c and the angles between them `alpha, beta and gamma` respectively. Based on this, there are seven crystal systems. In a cubic unit cell: `a=b=c and alpha = beta=gamma=90^(@)` The number of points in simple, body centred and face centred cubic cells are 1,2 and 4 respectively In both the hcp and ccp of spheres, the number of tetrahedral voids per sphere is two while the octahedral voids is one. A double triangular void surrounded by three spheres above and three spheres below is calledA. triangular voidB. tetrahedral voidC. octahedral voidD. trigonal bipyramidal void. |
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Answer» Correct Answer - C A double triangular void surrounded by 6 spheres is octahedral void. |
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| 905. |
The composition of a sample of wrustite is `Fe_(0.93)O_(1.00)`.Percentage of iron present in the form of iron (III) is nearlyA. 85B. 15C. `7.00`D. `93.00` |
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Answer» Correct Answer - 2 Let, the sample contains 93 Iron ions and 100 oxide ions. Total negative charge on oxide ions`=100xx-2=-200` No. of `Fe^(+3)`ions=x No. of `Fe^(+2)` iron ions =93-x Total positive charge `=x(+3)+(93-x)(+2)` Numarically +ve charge and -ve charge are equal `therefore 3x+(93-x)2=200 therefore x=14` % of `Fe^(+3)=(14)/(93)xx100=15.05%` |
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| 906. |
What is true about a bcc unit cell?A. The number of atoms in the unit cell is `2`.B. In addition to an atom at the centre of the body, in a unit cell there are `8` atoms at `8` different corners.C. One-eighth of an atom at a corner of the unit cell.D. None of the above. |
| Answer» Correct Answer - A::B::C | |
| 907. |
What is true about simple cubic type of unit cells?A. Eight constituents are at different corners of the cube.B. `Z_(eff) = 1`.C. Contribution by one corner is `(1)//(8)th` of an atom`.D. None of the above. |
| Answer» Correct Answer - A::B::C | |
| 908. |
Which of the following is//are convalent solids?A. `Fe`B. DiamondC. `NaCl`D. Graphite |
| Answer» Correct Answer - B::D | |
| 909. |
Select the correct statement(s).A. The non-stoichiometric from of `NaCl` is yellow and that of `KCl` is blue-lilac.B. Solids containing `F`-centres (Farbe) are paramagentic.C. Non-stoichiometric compounds are called Berthollide compounds.D. Conduction by electrons is called `n`-type semiconductor. |
| Answer» Correct Answer - A::B::C::D | |
| 910. |
Which is/are not amorphous solid(s)?A. RubberB. GraphiteC. GlassD. Plastics |
| Answer» Correct Answer - B | |
| 911. |
Which of the following statements is/are correct?A. If three `Fe^(2+)` ions are missing from their lattice in`FeO`, then there must be two `Fe^(3+)` ions somewhere in the lacttice.B. Crystals with matal deficiency defects are called super conductors.C. Crystals with metal deficiency are called semiconductors.D. `1` Bohr Magneton `= 9.27 xx 10^(-24) A m^(2)` |
| Answer» Correct Answer - A::C::D | |
| 912. |
Non-stoichiometric compounds areA. `Cu_(2)O`B. `Cu_(2)S`C. `FeO`D. `Hg_(2)Ba_(2)YCaCu_(2)O_(7)` |
| Answer» Correct Answer - A::B::C::D | |
| 913. |
Recently discovered superconductivity materials areA. `M_(3)C_(60)`B. `YBa_(2)Cu_(3)O_(7)`C. `SiC`D. `Hg_(2)Ba_(2)YCaCu_(2)O_(7)` |
| Answer» Correct Answer - A::B::D | |
| 914. |
If a mixture of `LiCl` and `NaCl` is malted and then cooled,A. A solid solution is formed.B. Mixture formed is called eutectic mixture.C. `TiO_(1.8)` is non-stoichiometric solid solution of `Ti_(2)O_(3)` and `TiO_(2)`.D. Neither `LiCl` nor `NaCl` separates. |
| Answer» Correct Answer - A::B::C::D | |
| 915. |
The effective radius of an iron atom is 1.42 Å . It has rock salt like structure. Calculate its density ( Fe = 56 amu) |
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Answer» Correct Answer - `2.16 " g cm"^(-3)` Rock salt type structure means fcc for which ` r= a/(2sqrt2) = 0.3535 a or a = r/0.3535 or a = r/ 0.3535 = ( 142"pm")/0.3535 = 401 . 7 "pm"` For fcc , Z = 4 |
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| 916. |
The effective radius of an iron atom is `1.42 Å`. It has a rock-salt structure. Calculate its density (Fe = 56) |
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Answer» Due to rock-salt (fcc) structure, number of atoms in a unit cell (z) = 4 Thus, `d ("density") = (zM)/(a^(3)N_(0)) " " a = 2 sqrt2 r = 2 sqrt2 xx 1.42 xx 10^(-8) cm` `:. D = (4 xx 56)/(6.02 xx 10^(23) xx (2 sqrt2 xx 1.42 xx 10^(-8))^(3)) = 5.743 g //cm^(3)` |
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| 917. |
An alloy of copper, silver and gold is found to have copper constituting the ccp lattice. It gold atoms occupy the edge centres and silver is persent at body centre, the alloy has a formulaA. `Cu_(4)Ag_(2)Au`B. `Cu_(4)Ag_(4)Au`C. `Cu_(4)Au_(3)Ag`D. `cuAg_(3)Au` |
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Answer» Correct Answer - C No. ofCu atoms in the unit cell (fcc/ccp) `=(8xx(1)/(8))+(6xx(1)/(2))=4` Au atoms occupying the edge centres `=12xx(1)/(4)=3` Ag atom present at the body centre = 1. Hence, the formula is `Cu_(4)Au_(3)Ag` . |
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| 918. |
Two ionic solids `AB` and `CB` crystallize in the same lattice. If `r_(A^(o+))//r_(B^(ɵ))` and `r_(C^(o+))//r_(B^(ɵ))` are `0.50` and `0.70`, respectively, then the ratio of edge length of `AB` and `CD` isA. `0.68`B. `0.78`C. `0.88`D. `0.98` |
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Answer» Correct Answer - C `r_(A^(o+))/(r_(B^(ɵ)))=0.50` and `r_(C^(o+))/(r_(B^(ɵ)))=0.70` `rArr (r_(A^(o+)) xx r_(B^(o+)))/(r_(B^(ɵ))) = 1+0.5 = 1.5` Similarly, `rArr (r_(AC^(o+)) xx r_(B^(o+)))/(r_(B^(ɵ)) = 1 + 0.5 = 1.70` `:. (r_(A^(o+)) + r_(B^(o+)))/(r_(C^(o+)) + r_(B^(ɵ)))=(1.5)/(1.7) = 0.88` Also, `a_(AB) = 2(r_(A^(o+)) + r_(B^(o+)))` and `a_(CB) = 2(r_(C^(o+)) + r_(B^(ɵ)))` and `a_(CB) = 2(r_(C^(o+)) + r_(B^(ɵ)))` `:. (a_(AB))/(a_(CB)) = (1.5)/(1.7) = 0.88` |
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| 919. |
Silicon dopped with group `13` and group `15` member element is, repectively, called …… semiconductorA. `p`-type, `n`-typeB. `n`-type, `p`-typeC. `p`-typeD. `n`-type |
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Answer» Correct Answer - A `p-`type |
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| 920. |
A molecule `A_(2)B (Mw = 166.4)` occupies triclinic lattice with `a = 5 Å, b = 8 Å`, and `c = 4 Å`,. If the density of `AB_(2)` is `5.2 g cm^(-3)`, the number of molecules present in one unit cell isA. `2`B. `3`C. `4`D. `5` |
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Answer» Correct Answer - B Volume of unit cell ` = a xx b xx c = 5 xx 10^(-8) xx 8` ` xx 10^(8) xx 4 xx 10^(-8)` `= 1.6 xx 10^(-22) cm^(3)` Mass of unit cell `= 1.6 xx 10^(-22) cm^(3)` Mass of unit cell `= 1.6 xx 10^(-22) xx 5.2 = 8.32 xx 10^(-22)g` Number of molecules in one unit cell `= (8.32 xx 10^(-22)g)/(166.4 g mol^(-1))` `= 3` |
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| 921. |
The percentage of empty space in a body centred cubic arrangement is :A. 74B. 68C. 32D. 26 |
| Answer» Correct Answer - C | |
| 922. |
In which of the following crystals, alternate tetrahedral voids are occupied?A. `NaCl`B. `ZnS`C. `CaF_(20`D. `Na_(2)O` |
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Answer» Correct Answer - B In `ZnS` structure, sulphide ions occupy all the lattice points while `Zn^(2+)` ions are present in alternate tetrahedral voids. |
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| 923. |
The empty space in the hexogonal close packing is……..% while that in the body-centred cubic packing is ………% |
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Answer» Correct Answer - 0.542 or 52.4 % |
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| 924. |
The molar volume of KCl and NaCl are `37.46` mL and `27.94`mL respectively . The ratio of the unit cube edges of the two crystals isA. `1.296`B. `1.116`C. `1.341`D. `0.950` |
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Answer» Correct Answer - B `((a_(1))/(a_(2)))^(3)=(V_(1))/(V_(2))` |
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| 925. |
The ratio of anion radius to cation radius of a crystal is 10:9,3. then , the coordination number of the cation in the crystal isA. 2B. 4C. 6D. 8 |
| Answer» Correct Answer - 4 | |
| 926. |
Which one of the following ratio gives the purity of the metal (`rho`-resistivity (or) specific resistance)A. `(rho_(300^(@)C))/(rho_(4.2^(@)C))`B. `(rho_(300k))/(rho_(4.2K))`C. `(rho_(27k))/(rho_(4k))`D. `(rho_(300k))/(rho_(4^(@)C))` |
| Answer» Correct Answer - 2 | |
| 927. |
Which of the following is correct statementA. silicon doped with boron is p-type semiconductorB. silicon doped with arsennic is a n-type semiconductorC. metals are not good conductors of elelctricityD. electrical conductivity of semiconductors decreases with increasesing temperature. |
| Answer» Correct Answer - 1 | |
| 928. |
The cubic unit cell of a metal (molar mass= 63.55 `"mol"^(-1)`) has an edge length of 362pm. Its density is `8.92gcm^(-3)`. The type of unit cell isA. PrimitiveB. Face centredC. Body centredD. End centred |
| Answer» Correct Answer - 2 | |
| 929. |
The fraction of volume occupied by atoms in a face centered cubic unit cell is:A. 0.32B. 0.48C. 0.68D. 0.74 |
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Answer» Correct Answer - D |
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| 930. |
A metallic element crystallises into a lattice having a ABC ABC …… pattern and packing of spheres leaves out voids in the lattice. What type of structure is formed by this arrrangement ?A. 0.24B. 0.26C. 0.34D. 0.74 |
| Answer» Correct Answer - 0.02 | |
| 931. |
A metallic element crystallises into latticee containing a sequence of layers of ABABAB…… packing of spheres leaves out voids in the lattice. What precentage by volume fo the lattice is empty space ? |
| Answer» Correct Answer - 0.26 | |
| 932. |
A compund is made of two elements `P` and `Q` are in `ccp` arrangement while atoms `P` occupy all the tetrahedral voids. What is the formula of the compound? |
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Answer» First method Number of `Q` atoms in `c cp = 4//"unit cell"` Number of `TV_(s) = 8//"unit cell"` Number of `OV_(s) = 4//"unit cell"` Number of `P` atoms `=` Number of `TV_(s) = 8` Thus Formula`= P_(8) Q_(4) implies P_(2)Q` Second method Let number of `Q` atom in `c cp = 1//"atom"` Number of `TV_(s) = 2//"atom"` Number of `OV_(s) = 1//"atom"` Number of `P` atoms `=` Number of `TV_(s) = 2` Thus, formula `= P_(2)Q` |
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| 933. |
In a crystal, some ions are missing from normal sites. This is an example of `:`A. extended defectB. Intersitital defectC. Frenkel defectD. Schottky defect |
| Answer» Correct Answer - 4 | |
| 934. |
Which of the following is a ferromagnetic compound.A. `Fe_(2)O_(3)`B. `Fe_(3)O_(4)`C. `Cr_(2)O_(3)`D. `CrO_(2)` |
| Answer» Correct Answer - 4 | |
| 935. |
The empty space between the shaded balls and hallow balls as shown in the diagram is called: A. hexagonal voidB. octahedral voidC. tetrahedral voidD. double triangular void |
| Answer» Correct Answer - B | |
| 936. |
Which of the following statements is not true abor amorphous solids?A. The constituent particles are arranged in a regular fashion containing short range as well as long range orderB. When kept for a long time time , they may become crystallineC. They are be moulded by heatingD. They are isotropic in nature |
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Answer» Correct Answer - a The constituent particle are not arranged in any regular fashion there may be at must short range order only. |
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| 937. |
Which of the following exists as covalent crystals in the solid state?A. SulphurB. PhosphorusC. lodineD. Silicon |
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Answer» Correct Answer - d Sillon `(Si)` cvalent solid `(S)` molecular solid Phophoras `(P_(4))` molecular solid lodine`(l_(1))` molecular solid. |
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| 938. |
Diamond is hard becauseA. All the four valence electrons are bonded to each carbon atom by covalent bondsB. It is a giant moleculeC. It is made up of carbon atoms.D. It cannot be burnt. |
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Answer» Correct Answer - A In diamond, each carbon atom is in `sp^(3)` hybridized state and linked to four other carbon atoms tetrahedrally by covalent bonds. As the atoms are held firmly by strong covalent bonds. So diamond is hardest substance. |
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| 939. |
Which of the following statements are false ?A. The radius of a metal atom is taken as half the nearest metal`-` metal distance in a metallic crystalB. One tetrahedral void per atom is present in `h.c.p.` structureC. In the fluorite structure `(CaF_(2)),` the `Ca^(2+)` ions are located at the lattice points and the fluoride ions fill all the tetrahedral holes in the `c.c.p.` crystalD. In the antifluorite structure `(Li_(2)O,Rb_(2)S)` the cations are located at the lattice points and anions fill the tetrahedral holdes in the `c.c.p.` structure. |
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Answer» Correct Answer - b,d b,d |
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| 940. |
Which of the following statements are correct ?A. The co-ordination number of each type of ions in CsCl crystals is 8B. A metal which crystallises in bcc structure has co-ordination number of 12C. A unit cell of an ionic crystals shares some of its ions with other unit cellsD. The length of a unit cell in NaCl is 552pm `(r_(Na^(+))=95 "pm" r_(Cl^(-))=181"pm")` |
| Answer» Correct Answer - A::C::D | |
| 941. |
Which of the following statements are correct ?A. The cations occupy more space than atoms in crystal packingB. In Schottky defect, equal number of cation and anion vacancies are presentC. Ionic solids show change in density due to Frenkel defect.D. An increase in pressure on `NaCl` crystal, the `6:6` co`-` ordination changes to `8:8` co`-` ordination |
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Answer» Correct Answer - a,b,d In Frenkel defect no ions are missing from the crystal as a whole and thus, there is no charge in density |
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| 942. |
Which is true ?A. Piezoelectricity is due to net - dipole movementB. Some electric current is produced on heating polar crystals, this is pyro electricityC. Ferroelectricity is due to allignment of dipole in the same directionD. Ferrielectricity is due to alligment of dipole in the same direction |
| Answer» Correct Answer - A::B::C | |
| 943. |
Choose the correct statements out of the followingA. Quartz is a three dimensional silicateB. There is no effect of density on the solid having Frenkel defectC. Group 14 elements doped with group 13 elements produce n-type semi conductorsD. Ferrimagnetic substances possess large magnetic moment |
| Answer» Correct Answer - A::B | |
| 944. |
A solid made up of ions of `A` and `B` possess edge length of unit cell of `0.5664nm` has four formula units. Among the two ions, the smaller one occupy the interstitial void and the larger ions occupy the space lattice with ccp type of arrangement. One molecule of solid has mass `9.712xx10^(-23)g.` The ionic radius for `A^(+)` ion is `:`A. `0.755Å`B. `0.625Å`C. `0.826Å`D. `0.914Å` |
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Answer» Correct Answer - c `r_(A-B)=2.82` `:.r_(A^(+))=2.82-1994=0.826Å` |
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| 945. |
A solid made up of ions of `A` and `B` possess edge length of unit cell of `0.5664nm` has four formula units. Among the two ions, the smaller one occupy the interstitial void and the larger ions occupy the space lattice with ccp type of arrangement. One molecule of solid has mass `9.712xx10^(-23)g.` The density of solid is `:`A. `2.16g//cm^(3)`B. `0.54g//cm^(3)`C. `1.08g//cm^(3)`D. `1.562g//cm^(3)` |
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Answer» Correct Answer - a The density of solid `=(nxxat.wt.)/(Av. no . xxa^(3))` `=(4.9.712xx10^(-23)xx6.023xx10^(23))/(6.023xx10^(23)xx(0.564xx10^(-9)xx10^(2))^(3))` `=2.16g//cm^(3)` |
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| 946. |
Find the number of `Na^(+)` ions and `Cl^(-)` ions associated with each in a unit cell and `NaCl`. |
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Answer» Correct Answer - 4 `NaCl` has `f.c.c.` structure, 8 at the corners is shared by 8 unit cells. Each of six sodium ion at `f.c.c.` is shared by two unit cells. `:. `No. of `Na^(+)` ions in each unit cell`=(8)/(8)+(6)/(2)=4` `12Cl^(-)` ions at the middle of each of cell is shared by 4 cells and `Cl^(-)` ion at the centre is wholly belong to it. `:.` No. of `Cl^(-)` ions in unit cell `=(12)/(4)+1=4` |
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| 947. |
A solid `A^(o+)B^(ɵ)` has `NaCl`-type close-packed structure. If the radius of the cation is `90` pm, calculate the probable range of the radius of the anion. |
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Answer» Correct Answer - `123.3` to `217.4 pm` `NaCl` has fcc-type structure. The ideal limiting radius ratio is `0.414`. `(r_(o+))/(r_(ɵ)) = 0.414` `r_(ɵ) = (90)/(0.414) = 217.4` pm When the structure is nor ideally close packed (i.e., anions do not touch each other) the limiting ratio can be upto `0.73`. Minimum raudys of anion `= (r_(o+))/(0.73) = (90)/(0.73) = 123.3` pm |
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| 948. |
if `a=b ne c` and `alpha=beta=gamma=90^(@)`, the crystal system isA. cubicB. rhombicC. tetragonalD. monoclinic |
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Answer» Correct Answer - 3 In tetragonal system `a=bnec` and `alpha=beta=gamma=90^(@)` examples are `Sn` (white tin) `SnO_(2)TiO_(2)` Cubic system :`a=b=c` and `alpha=beta=gamma=90^(@)` Rhombic system :`a ne b ne c` and `alpha=beta=gamma=90^(@)` Monoclinic system :`a ne b ne c` and `alpha=gamma=90^(@),beta=120^(@)` |
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| 949. |
Substance which is weakly repelled by a magnetic field isA. `O_(2)`B. `H_(2)O`C. `CrO_(2)`D. `Fe_(3)O_(4)` |
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Answer» Correct Answer - a Substance which is weakly repelled by a magnetic field is diamgagnetic , e.g, ` H_(2)O` |
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| 950. |
Calcium metal crystallizes in a face -centred cubic lattice with edge of 0.556 nm. Calculate the density of the metal if it contains (i) 0.5 % Frenkel defects (ii) 0.2 % Schottky defects . |
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Answer» (i) Frenkel defects have no effect on the density because number of atoms per unit cell remains the same. For FCC, Z = 4 , For Ca, M = ` 40 " g mol"^(-1)` Also, a = 0.556 nm = ` 0.556 xx 10^(-7)` cm. Density , ` p = (Z xx M)/(a^(3) xx N_(0)) = (( 3.992) ( 40 " g mol"^(-1)))/(( 0.556xx 10^(-7) cm)^(3) ( 6.022 xx 10^(23) "mol"^(-1))) = 1.5427 " g cm"^(-3)` |
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