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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.
| 1. |
Iodine molecules are held in the crystal lattice by:A. London forcesB. dipole -dipole interactionsC. covalent bondsD. coulombic forces |
| Answer» Correct Answer - A | |
| 2. |
The edge of unit of `FC C Xe` crystal is 620 pm .The radius of Xe atom isA. 213.25 pmB. 235.16 pmC. 189.37 pmD. 209.87 pm |
| Answer» Correct Answer - A | |
| 3. |
Classify the following solids into four categories based on intermolecular forces of interaction. Caesium chloride, Solid carbon disulphide , Bronze ,Neon ,Boron nitride, Washing soda , Carborundum , Corrudum , Solid `NH_3`, Solid camphor , Silver , Silica |
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Answer» (i)ionic solids : `Na_2CO_3 .10H_2O , CsCl` , currundum (ii)Covalent solids : Boron nitride (BN) , silica , carborundum (sic) (iii)Metallic solids: Silver , Bronze (iv)Molecular solids : Solids `CS_2` , Solid neon, solid camphor |
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| 4. |
which of the following statemets is not true about the hexagonal close packing ?A. In hcp, atoms occupy 74% the available spaceB. It is AB AB type packing in which third layer is aligned with the first layerC. Be, Mg, Mo etc. are found to have hcp structureD. The coordination number is 6 |
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Answer» Correct Answer - D The coordination number is 12 |
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| 5. |
Observe the given figure carefully and fill in the blanks by choosing the correct option . A. `{:("(p)","(q)","(r)"),("Perfect crystal","p-type semiconductor","n-type semiconductor") :}`B. `{:("(p)","(q)","(r)"),("Doped crystal","n-type semiconductor","p-type semiconductor") :}`C. `{:("(p)","(q)","(r)"),("Perfect crystal","n-type semiconductor","p-type semiconductor") :}`D. `{:("(p)","(q)","(r)"),("n-type semiconductor","Perfect crystal ","p-type semiconductor") :}` |
| Answer» Correct Answer - C | |
| 6. |
Fill in the blanks by choosing the correct option . Metals often occur in ___x___ condition. Individual crystals are randomly oriented so a metallic sample may appear to be __y___ even though a single crystal is __z__A. x-crystalline , y-isotropic , z-anisotropicB. x-polycrystalline , y-isotropic , z-anisotropicC. x-anisotropic, y-isotropic , z-crystallineD. x-crystalline , y-anisotropic , z-isotropic |
| Answer» Correct Answer - B | |
| 7. |
Study the figure of a solid given below depicting the arrangement of particles. Which is the most appropriate term used for the figure ? A. IsotropyB. AnisotropyC. Irregular shapeD. Amorphous nature |
| Answer» Correct Answer - B | |
| 8. |
A compound having bcc geometry has atomic mass 50. Calculate the density of the unit cell if its edge length is 290 pm. |
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Answer» For bcc geometry number of atoms per unit cell (Z)=2 Atomic mass (A) =50 Edge length (a)=`290xx10^(-10)` cm Density `(rho)`=? `rho=(ZxxA)/(N_0xxa^3)=(2xx50)/(6.02xx10^23xx(290xx10^(-10))^3=6.83 g//cm^3` |
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| 9. |
An element occurs in BCC with edge length 300 pm. The density of solid is `"7.2 g cm"^(-3)`. Find out (a)Number of atoms in foil of `27 cm^2` area and 1 cm thickness. (b)Number of unit cells in the foil . (c )Number of atoms in a foil of 100 g. |
| Answer» (a)`2xx10^24` atoms , (b)`1xx10^24` unit cells , (c ) `1.02xx10^24` atoms | |
| 10. |
A metal crystallises in a bcc lattice ,its unit cell edge length in about `300` pm and its molar mass is about `50g mol^(-1)` what would be the density of the metal (in g `cm^(-3))`?A. `"10 g cm"^(-3)`B. `" 14.2 g cm"^(-3)`C. `"6.15 g cm"^(-3)`D. `"9.32 g cm"^(-3)` |
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Answer» Correct Answer - C `d=(ZxxM)/(a^3xxN_A)` For bcc structure, Z=2 `d=(2xx50)/(6.023xx10^23xx(300xx10^(-10))^3)=6.15 g cm^(-3)` |
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| 11. |
A metal X crystallises in a face-centred cubic arrangement with the edge length 862 pm. What is the shortest separation of any two nuclei of the atom ?A. 406 pmB. 707 pmC. 862 pmD. 609.6 pm |
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Answer» Correct Answer - D For fcc arrangement , distance of nearest neighbour (d) is `a/sqrt2=862/1.414`=609.6 pm |
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| 12. |
Match the column I having type of lattice point and its contribution to one unit cell in column II and mark the appropriate choice . A. A-(ii),B-(i),C-(iii),D-(iv)B. A-(ii),B-(iii),C-(iv),D-(i)C. A-(i),B-(ii),C-(iv),D-(iii)D. A-(iii),B-(iv),C-(i),D-(ii) |
| Answer» Correct Answer - B | |
| 13. |
Mark the incorrect pair from the following.A. Schottky defect- Equal number of cations and anions are missingB. Frenkel defect - Dislocation of cation from its normal site to an interstitial siteC. Impurity defect- `CdCl_2` in AgCl crystal to create cationic vacancyD. Metal excess defect - `Fe_(0.93)O` |
| Answer» Correct Answer - D | |
| 14. |
A compound `M_(p)X_(q)` has cubic close packing `(ccp)` arrangement of `X`. Its unit cell structure is shown below. The empirical formula of the compound is A. MXB. `MX_2`C. `M_2X`D. `M_5X_14` |
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Answer» Correct Answer - B 8 X atoms present at the cornes. Atoms contribute to 1 unit cell =`1/8xx8`=1 6 X atoms present at the face centres. Atoms contribute to 1 unit cell = `6xx1/2`=3 Total X atoms = 3+1 =4 4 M atoms present at edge centres. Atoms present in 1 unit cell `=4xx1/4=1` 1 M atom present at body centre and it contribute completely to 1 unit cell . Thus, total M atoms in one unit cell = 1+1=2 Ratio is M :X : : 2 : 4 : : 1:2 Thus, empirical formula is `MX_2` |
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| 15. |
Three type of bands are shown in the figures given below showing the position of the valence band and conduction band. The figures A,B and C represent A. A-Non-metal , B-Metal ,C-SemiconductorB. A-Semiconductor , B-Insulator , C-ConductorC. A-Metal , B-Insultor , C-SemiconductorD. A-Insulator , B-Conductor , C-Semiconductor |
| Answer» Correct Answer - C | |
| 16. |
To get a n- type semiconductor from silicon , it should be doped with a sustance with valency……….. .A. galliumB. arsenicC. aluminiumD. boron |
| Answer» Correct Answer - B | |
| 17. |
Which of the following statements are true about semiconductors?A. Impurity of lower group creates n-type semiconductorsB. Impurity of higher group creates p-type semiconductorsC. Extrinsic semiconductors are formed by doping impurityD. Intrinsic semiconductors become conductors when temperature is raised |
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Answer» Correct Answer - D Intrinsic semiconductors are insulators at room temperature and become semiconductors when temperature is raised. |
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| 18. |
which of the following represents correct order of conductivity in solids ?A. `K_("metals")gt gt K_("insulators") lt K_("semiconductors")`B. `K_("metals")lt lt K_("insulators") lt K_("semiconductors")`C. `K_("metals"), K_("semiconductors") gt K_("insulators")="zero"`D. `K_("metals")lt K_("semiconductors") gt K_("insulators")ne"zero"` |
| Answer» Correct Answer - A | |
| 19. |
The conductivity of intrinsic semiconductors can be increased by adding a suitable impurity. This process is called __(P)__. This can be done with an impurity which is __(Q)_ rich or deficient as compared to the semiconductor. Such impurities introduce __(R)__ defects in them. Electron rich impurities result in __(S)__ type semiconductors while electron deficit impurities result in __(T)___ type semiconductors .A. P-doping , Q-proton , R-point , S- p , T-nB. P-doping , Q-electron , R-non-stoichiometric , S- p , T-nC. P-energy gap , Q- charged , R-impurity , S-n , T-pD. P-doping , Q-electron , R-electronic , S-n , T-p |
| Answer» Correct Answer - D | |
| 20. |
Pure silicon and germanimum areA. conductorsB. semiconductorsC. insulatorsD. piezoelectric crystals |
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Answer» Correct Answer - C Pure Si and Ge are insulators because of the absence of any hole or free electron. They show semiconductor behaviour only after doping |
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| 21. |
Which of the following shows correct range of conductivity ? (i)Conductors : `10^4` to `10^7 ohm^(-1) m^(-1)` (ii)insulators : `10^(-6)` to `10^4 ohm^(-1) m^(-1)` (iii)Semiconductors : `10^(-10)` to `10^(-6) ohm^(-1) m^(-1)`A. (i) and (ii)B. (i) onlyC. (ii) and (iii)D. (i), (ii) and (iii) |
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Answer» Correct Answer - B Conductors : `10^4` to `10^7 ohm^(-1) m^(-1)` Insulators: `10^(-20)` to `10^(-10) ohm^(-1) m^(-1)` Semiconductors: `10^(-6)` to `10^4 ohm^(-1) m^(-1)` |
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| 22. |
Assertion: Metals are generally good conductors of electricity Reason: Electrical conductivity of metals is due to Schottky type of defectsA. Statement-1 is true, statement-2 is true, statement-2 is a correct explanation for statement-1B. Statement-1 is true, statement-2 is true, statement-2 is not correct explanation for statement-1C. Statement-1 is true, statement-2 is falseD. Statement-1 is false, statement-2 is true |
| Answer» Correct Answer - C | |
| 23. |
`Fe_(3)O_(4)` is ferrimagnetic at room temperature but at 850K it becomes::A. diamagneticB. ferrimagneticC. paramagneticD. anti-ferromagnetic |
| Answer» Correct Answer - C | |
| 24. |
In corundum, oxide ions are arranged in hexagonal close packing and aluminium ionsa occpy tow-third of the octaheral voids. What is the formula of corrundum ? . |
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Answer» Number of oxides per unit cell = 6 Number of octahedral voids per unit cell=6 Number of `Al^(+3)` ions in octahedral voids=`(6xx2)/3=4` `therefore Al^(+3) : O^(-2)` 4 :6 or 2 :3 Hence, formula is `Al_2O_3` |
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| 25. |
How many aluminium ions are present per unit cell of corundum `(Al_2O_3)` ? |
| Answer» Correct Answer - D | |
| 26. |
In a solid lattice the cation has left a lattice sirte and is located at an interstital position , the lattice defect isA. Interstitial defectB. Schottky defectC. Valency defectD. Frenkel defect |
| Answer» Correct Answer - D | |
| 27. |
The crystal system for which `a!= b!= c and alpha = beta = gamma = 90^(@)` is said to beA. CubicB. TetragonalC. OrthorhombicD. Hexagonal |
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Answer» Correct Answer - C In orthorhombic crystal system, `a ne b ne c` but axial angles `alpha, beta ` and `gamma` are equal and `90^@` |
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| 28. |
For the structure given below, the site marked as `S` is a `:` A. tetrahedral voidB. cubic voidC. octahedral voidD. none of these |
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Answer» Correct Answer - C Octahedral voids occupy the position of edge centre and body centre |
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| 29. |
In seven pssible crystal system hoe many crystal system have more than one Bravais lattic ?A. HexagonalB. TriclinicC. RhombohedralD. Monoclinic |
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Answer» Correct Answer - D Monoclinic crystals have two Bravais lattices - Primitive and end centred |
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| 30. |
Which types of Bravais lattice is not present in cubic crystal system ? |
| Answer» Correct Answer - End Face centred | |
| 31. |
Name the type of crystal systems of NaCl and Borax. |
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Answer» NaCl =Cubic Borax = Mono clinic |
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| 32. |
Graphite cannot be classified as :A. conducting solidB. network solidC. covalent solidsD. ionic solid |
| Answer» Correct Answer - D | |
| 33. |
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 - B | |
| 34. |
A crystal is formed by two elements X and Y in cubic structure. X atoms are at the corners of a cube while Y atoms are at the face centre . The formula of the compound will beA. XYB. `XY_2`C. `X_2Y_3`D. `XY_3` |
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Answer» Correct Answer - D No. of X atom (at the corners) = `1/8` x 8 =1 No. of Y atoms (fcc) = `6xx1/2`=3 hence, the formula is `XY_3` |
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| 35. |
A compound formed by element `X` and `Y` crystallizes in the cubic structure when `Y` atoms are at the corners of the cube and `X` atoms are at the alternate faces. What is the formula of the compound? |
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Answer» Number of Atoms of A =`8xx1/8`=1 Number of Atoms of B =`2xx1/2` = 1 `therefore` A:B=1:1 Hence formula =AB |
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| 36. |
Tungsten has a body centered cubic lattice and each lattice point is occupied by one atom. Calculate the radius of metallic tungsten if density of tungsten is `"19.30 g cm"^(-3)` and atomic weight is 183.9 g. |
| Answer» Correct Answer - 1.37 Å | |
| 37. |
An alloy of copper and gold crystallizes in cubic lattic, in which the `Au-` atoms occupy the lattice points at the corners of cube and `Cu-` atoms occupy the centre of each face. The formula of this alloy is `:` |
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Answer» Number of gold atoms from 8 corners =1 Number of copper atoms from 6 faces =3 `therefore` Formula =`AuCu_3`. |
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| 38. |
Calculate the closest distance between two gold atoms (edge length =1.414 Å) in a face-centered cubic lattice of gold |
| Answer» Correct Answer - 1 Å | |
| 39. |
Element x,y and z crystallize in primitive , face centered and body centered unit cell respectively. What would be the correct order of metallic radii of each unit cell is ?A. `r_x gt r_z gt r_y`B. `r_y gt r_z gt r_x`C. `r_x gt r_y gt r_z`D. `r_y gt r_x gt r_z` |
| Answer» Correct Answer - A | |
| 40. |
Which of the following is/are correct for fluorite structure `(CaF_2)` ?A. `Ca^(2+)` ions are in ccp with fcc unit cell and `F^-` ions occupy all the tetrahedral voidsB. `Ca^(2+)` ion is surrounded by `4F^-` ionsC. Mass of one unit cell = mass of `4Ca^(2+)` + Mass of `4F^-`D. C.N. of `F^-`=4 , C.No . `Ca^(2+)`=8 |
| Answer» Correct Answer - A::D | |
| 41. |
In `CaF_(2)` type (fluorite structure) `Ca^(2+)` ions form W structure and `F^(-)` ions are present in all X voids. The coordination number of `Ca^(2=)` is Y and `F^(-)` is Z. W,X,Y and Z respectively areA. A-ccp, B-octahedral , C-8,D-4B. A-bcc, B-tetrahedral , C-4,D-8C. A-ccp , B-tetrahedral , C-8,D-4D. A-ccp, B-octahedral , C-4,D-8 |
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Answer» Correct Answer - C `Ca^(2+)` ions form ccp structure while `F^-` ions are in all tetrahedral holes and coordination numbers are 8 and 4 |
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| 42. |
Assertion:Substances like `Fe_3O_4` and `MgFe_2O_4` lose ferrimagnetism on heating and become paramagnetic Reason : Magnetic moments of the domains in these substances are aligned in parallel and antiparallel directions in unequal numbers.A. If both assertion and reason are true and reason is the correct explanation of assertionB. If both assertion and reason are true but reason is not the correct explanation of assertion.C. If assertion is true but reason is falseD. If both assertion and reason are false |
| Answer» Correct Answer - A | |
| 43. |
In the cubic close close packing, the unit cell has....A. 4 tetrahedral voids each of which is shared by four adjacent unit cells .B. 4 tetrahedral voids within the unit cellC. 8 tetrahedral voids each of which is shared by four adjacent unit cellsD. 8 tetrahedral voids within the unit cells . |
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Answer» Correct Answer - D Cubic close packing is also called face centred cubic No. of atoms per unit cell in ccp (or fcc) = 4 `therefore` No. of tetrahedral voids= 2 x 4 =8 |
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| 44. |
Which of the following statements is not true ?A. Paramagnetic substances are weakly attracted by magnetic fieldB. Ferromagnetic substances cannot be magnetised permanentlyC. The domains in antiferromagnetic substances are oppositely oriented with respect to each otherD. Pairing of electrons cancels their magnetic moment in the diamagnetic substances . |
| Answer» Correct Answer - B | |
| 45. |
which of the follwing defects is also known as dislocation defect ?A. Frenkel defectB. Schottky defectC. Non-stoichiometric defectD. Simple interstitial defect |
| Answer» Correct Answer - A | |
| 46. |
A ferromagnetic substance becomes a permanent magnet when it is placed in a magnetic field because:A. all the domains get oriented in the direction of magnetic fieldB. all the domains get oriented in the direction opposite to the direction of magnetic fieldC. domains get oriented randomlyD. domains are not affected by magnetic field |
| Answer» Correct Answer - A | |
| 47. |
In a CCP structure of compound XY, X atoms are present at octahedral voids. Calculate the number of nearest neighbours upto 6th C.N. for an X atom located at body centre. |
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Answer» X `to` at O-voids `Y to` in CCP (i.e. at corners and at face centres ) 1st C.N.=6 ( Y at six face centres) 2nd C.N.=12 (X at 12 edge centres ) 3rd C.N.=8 (Y at 8 corners ) 4th C.N.=6 (X at six body centres of other adjacent unit cells) 5th C.N.=24 (Y at four adjacent face-centres of each of six adjacent unit cells ) 6th C.N.=24 (X at four adjacent edge-centres of each of six adjacent unit cells) |
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| 48. |
The interatomic distance for bcc crystal isA. aB. `a/2`C. `(sqrt3a)/2`D. `(2a)/sqrt3` |
| Answer» Correct Answer - C | |
| 49. |
which of the following favours the existenence of a substance in the solid state ?A. high temperatureB. Low temperatureC. High thermal energyD. Weak cohesive forces |
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Answer» Correct Answer - B At sufficiently low temperature , the thermal energy is low and intermolecular forces bring the particles so close that they cling to one another and occupy fixed positions. The particles can still oscillate about their mean positions and the substance exists in solid state. |
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| 50. |
Which of the following oxides shows electrical properties like metals ?A. `SiO_2`B. MgOC. `SP_(2(s))`D. `CrO_2` |
| Answer» Correct Answer - D | |