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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.
| 101. |
How many formula units are there in the unit cell of sodium chloride ?A. 2B. 4C. 6D. 8 |
| Answer» Correct Answer - B | |
| 102. |
Which of the following is/are true statement(s)?A. `KO_2` is orange coloured because of F-centresB. KCl is violet on heating with K-metal vapour because of F-centersC. Crystals with defects are better conductor of electricityD. CsCl also shows F-centre defect |
| Answer» Correct Answer - B::C | |
| 103. |
In the closest packing of atomsA. Coordination number of particles placed in of tetrahedral voids is smaller than octahedral voidsB. Size of tetrahedral void is larger than that of octahedral voidC. Size of voids depend upon size of atoms and tetrahedral void is smaller than octahedral voidD. Radius ratio for tetrahedral voids is smaller than octahedral void |
| Answer» Correct Answer - A::C::D | |
| 104. |
In graphics carbon atoms are joined togather due toA. Ionic bondingB. vander Waals forcesC. metallic bondingD. Covalent bonding |
| Answer» Correct Answer - D | |
| 105. |
which of the following is not true about the ionic solids ?A. Bigger ions form the close packed structureB. Smaller ions occupy either the tetrahedral or the octahedral voids depending upon their sizeC. Occupation of all the voids is not necessaryD. The fraction of octahedral or tetrahedral voids occupied depends upon the radii of the ions occupying the voids . |
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Answer» Correct Answer - D Number of tetrahedral voids are always double than octahedral voids. |
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| 106. |
For hcp lattice which statements will be correct ?A. Coordination number of hcp =12B. Volume of unit cell unoccupied =74%C. It contains both tetrahedral and octahedral voidsD. This is more effective packing than ccp |
| Answer» Correct Answer - A::C | |
| 107. |
In diamond , the C.N. of carbon and number of carbon atoms per unit cell respectively areA. 4,8B. 4,6C. 6,4D. 6,6 |
| Answer» Correct Answer - A | |
| 108. |
In ionic solids AB and CD , radius -ratios are x and y respectively. If x +y=0.75 and x-y=0.25 then cations in AB and CD are respectively inA. T-voids, O-voidsB. O-voids , T-voidsC. T-voids, T-voidsD. O-voids , O-voids |
| Answer» Correct Answer - B | |
| 109. |
In a HCP unit-cell, if total number of atoms per unit cell gets halved, then what is the percentage void in unit cell ? |
| Answer» Correct Answer - `63%` | |
| 110. |
If the total number of atoms per unit cell in an hcp structure and a bcc structure gets halved, then ratio of percentage voids in hcp and bcc structures isA. `34/27`B. `21/22`C. `22/21`D. `37/34` |
| Answer» Correct Answer - B | |
| 111. |
Which of the following statements is not correct about molecular crystals ?A. They are generally soft and easily compressibleB. They are good conductors of electricity as the electrons are delocalised in the bondsC. They have low melting and boiling pointsD. They consist of polar or non-polar molecules . |
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Answer» Correct Answer - B Molecular crystals are bad conductors of electricity as the electrons are localised in the bonds. |
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| 112. |
Which among the following will show anisotropy ?A. GlassB. NaBrC. PlasticD. Rubber |
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Answer» Correct Answer - B Only crystalline solids show anisotropy |
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| 113. |
AB crystallizes in a rock salt structure. The nearest distance between A and B is `Y^(1//3)` nm, where Y is a constant. The molecular mass of AB is `"6.023 Y g/mol"^(-1)` .Determine the density in `kgm^(-3)`. |
| Answer» Correct Answer - `"5.0 kg m"^(-3)` | |
| 114. |
In a crystalline solid, anions `B` are arranged in ccp structure. Cations `A` are equally distributed between octahedral and tetrahedral voids if all the octahedral voids are occupied the formula of the ionic solids will beA. ABB. `AB_2`C. `A_2B`D. `A_2B_3` |
| Answer» Correct Answer - C | |
| 115. |
An element (At. Mass =50 g/mol) having fcc structure has unit cell edge length 400 pm. The density of element isA. 5.188 g/ccB. 10.376 g/ccC. 2.56 g/ccD. 1.2 g/cc |
| Answer» Correct Answer - A | |
| 116. |
The edge length of a face centred unit cubic cell is 508 pm. If the radius of cation is 110 pm, the radius of anion will beA. 144 pmB. 288 pmC. 398 pmD. 618 pm |
| Answer» Correct Answer - A | |
| 117. |
Analysis shows that nickel oxide has the formula `Ni_(0.98)O_(1.00)`. What fractions of nickel "exist" as `Ni^(2+)` and `Ni^(3+)` ions?A. `96%`B. `4%`C. `98%`D. `2%` |
| Answer» Correct Answer - B | |
| 118. |
Quartz on strong heating followed by rapid cooling gives glass which is an amorphous solid becauseA. Glass is a super cooled liquidB. Glass does not have a sharp melting pointC. Silicate tetrahedral unit are shifted in randomly arranged patternD. Glass is a silicate of sodium |
| Answer» Correct Answer - C | |
| 119. |
Classify the following as amorphous or crystalline solids: polyurethane, naphtalene, benzoic acid, teflon, potassium nitrate, cellophane, polyvinyl chloride, fibre glass, copper. |
| Answer» Crystalline solids Benzoic acid, potassium nitrate, copper Amorphous solids. Polurethane, Teflon, cellophane, polyvinyl chloride, fibreglass. | |
| 120. |
Assertion: Quartz glass is crystalline solid and quartz is an amorphous solid Reason: Quartz glass has long range orderA. 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 |
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Answer» Correct Answer - D The structure of quartz is crystalline and that of quartz glass is amorphous . The two structures are almost indentical yet in case of amorphous quartz glass, there is no long range order. |
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| 121. |
Classify the following solids into amorphous or crystalline solids. Bakelite, Platinum , Camphor , Oxalic acid , Melamine formaldehyde, Alum , Neoprene, Sugar , Solid `CO_2` , Polythene. |
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Answer» (i)Crystalline : Platinum, camphor , oxalic acid , alum , sugar , solid `CO_2` (ii)Amorphous : Bakelite, melamine , formaldehyde, neoprene , polythene |
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| 122. |
Assertion:SiC has higher melting point than NaCl. Reason: SiC has stronger electrostatic forces of attraction.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 |
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Answer» Correct Answer - C SiC is an example of covalent network solid which has very strong covalent bonding . Such solids are very hard and have extremely high melting point . |
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| 123. |
Thermal conductivity of a solid has different values along different directions. What kind of solid is this ? Also comment on its melting point . |
| Answer» It is anisotropic or crystalline solid hence, it has sharpe m.p. | |
| 124. |
Statement-1:In a hexagonal close packing , third layer is identical to first layer. Statement-2: In a primitive unit-cell, the third nearest neighbours of an atom located at a corner are at the other end of face-diagonal. Statement-3: If the radius of cation is nearly equal to radius of anions, then most favourable arrangement is BCC.A. T T TB. F F TC. T F TD. T T F |
| Answer» Correct Answer - C | |
| 125. |
Assertion:Packing efficiency of body centred cubic structure is 68% Reason:68% is the maximum packing efficiency any crystal can haveA. 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 |
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Answer» Correct Answer - C fcc has 74% packing efficiency |
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| 126. |
Which is /are correct statement about zinc blende structure ?A. zinc ions occupy half of the tetrahedral sitesB. each `Zn^(2+)` ion is surrounded by six sulphide ionsC. each `S^(2-)` ion is surrounded by six `Zn^(2+)` ionsD. it has fcc structure |
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Answer» Correct Answer - A ZnS has a ccp structure . `S^(2-)` ions are present at the corners of the cube and centre of each face. `Zn^(2+)` ions occupy half of the tetrahedral sites. Each `Zn^(2+)` ion is surrounded by four `S^(2-)` ions and each `S^(2-)` ion is surrounded by four `Zn^(2+)` ions. |
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| 127. |
In `CsCI` lattice the coordination number of `Cs` ion isA. 8,8B. 4,4C. 6,6D. 8,4 |
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Answer» Correct Answer - A CsCl has a bcc structure . Each `Cs^+` ion is surrounded by 8 `Cl^-` ions and each `Cl^-` ion is surrounded by 8 `Cs^+` ions. Thus, the structure has 8:8 coordination number. |
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| 128. |
Assertion : `CsCI` has body - centred cunic arrangement Reason: `CsCI` has one and `8 CI^(-)`ion is its unit cellA. 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 |
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Answer» Correct Answer - C CsCl has one `Cs^+` ion and one `Cl^-` ion in its unit cell. |
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| 129. |
A compound formed by two elements `M` and `N`. Element `N` forms ccp and atoms of `M` occupy `1//3rd` of tetrahedral voids. What is the formula of th compound?A. `Y_2Z_3`B. `YZ`C. `YZ_3`D. `Y_2Z` |
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Answer» Correct Answer - A Suppose no. of atoms of Z =a No. of tetrahedral voids = 2a No. of atoms of Y =`1/3xx2a="2a"/3` Ratio of atoms of Y and Z =`(2a)/3`:a=2:3 Hence, the formula of the compound =`Y_2Z_3` |
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| 130. |
Atoms of elements `B` from hep lattice and those of element `A` occupy two-thirds of tetrahedral voids. What is the formula of the compound formed by elements `A` and `B`? |
| Answer» The number of tetrahedral voids formed is equal to tiwice the number of atoms-of element B and only 2/3rd of these are occupied by the atoms of element. A. hence the ratio of the number of atoms of A and B is 2 x(2/3)1 or 4:3 and the formula of the compound is `A_(4)B_(3)`. | |
| 131. |
In a compound ,atoms of element Y from ccp lattice and those of element X occupy 2/3rd tetrahedral voids.The formula of the compound will be:A. `x_3y_4`B. `x_4y_3`C. `x_2y_3`D. `x_2y` |
| Answer» Correct Answer - B | |
| 132. |
In a solid AB, A atoms have a ccp arrangement and B atoms occupy all the octahedral sites. If all the face-centred atoms along one of the axes passing through body centres are removed, then what will be the resultant stoichiometry of compound ? |
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Answer» Number of A atoms constituting ccp=4 (1 from 8 corners and 3 from 6 face centres ) On removing two face centes along one of the axis Number of A atoms left in unit cell = 3 Number of B atoms occupying all octahedral voids =4 (3 from 12 edges centes and 1 froms body centre ) Hence, formula of compound is `A_3B_4` and stoichiometry is = 3:4 |
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| 133. |
Classify each of the following as being either a p-type or an n-type semiconductor a. Ge doped with In b. `B` doped with `Si` |
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Answer» 1. Ge is group 14 element and in is group 13 element Hence, an electron deficient hole is created and therefore, it is a p-type semiconductor. 2. B is group 13 element and Si is group 14element. There will be a free electron, so, it is an n-type semiconductor. |
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| 134. |
The appearance of colour in solid alkali metal halides is generally due toA. Frenkel defectB. Interstitial defectC. F-centresD. Schottky defect |
| Answer» Correct Answer - C | |
| 135. |
Why is Frenkel defect not found in pure alkali metal halides ?A. cations and anions have almost equal sizeB. there is a large difference in size of cations and anionsC. cations and anions have low coordination numberD. anions cannot be accommodated in voids. |
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Answer» Correct Answer - A Frenkel defect is not shown by alkali metals because cations and anions have almost same size and cations cannot be accommodated in interstitial sites . |
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| 136. |
What type of crystal defect is indicated in the diagram given below : `{:(Na^(+),Cl^(-),Na^(+),Cl^(-),Na^(+),Cl^(-)),(Cl^(-),square,Cl^(-),Na^(+),square,Cl^(-)),(Na^(+),Cl^(-),square,Cl^(-),Na^(+),Cl^(-)),(Cl^(-),Na^(+),Cl^(-),Na^(+),square,N^(+)):}`A. Frenkel defectB. Schottky defectC. Interstitial defectD. Cation excess defect |
| Answer» Correct Answer - B | |
| 137. |
The anionic sites occupied by unpaired electrons are called F-centres or colour centres . They impart __(X)__ colour to the crystals of NaCl. Excess of lithium makes LiCl crystals __(Y)__and excess of potassium makes KCl crystals _(Z)___. (X),(Y) and (Z) areA. yellow, green and pink respectivelyB. pink , yellow and violet (or lilac) respectivelyC. yellow, pink and violet (or lilac ) respectivelyD. red, yellow and pink respectively |
| Answer» Correct Answer - C | |
| 138. |
The appearance of colour in solid alkali metal halides is generally due toA. Schottky defectB. Frenkel defectC. Both Frenkel and Schottky defectsD. Cation excess defect |
| Answer» Correct Answer - C | |
| 139. |
which of the following solids is not an electrical conductor ? (a) Mg(s) (b) TiO(s) ( c) `I_(2)(s)` (d) `H_(2)O(s)`A. (I) onlyB. (II) onlyC. (III) and (IV)D. (II),(III) and (IV) |
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Answer» Correct Answer - C `I_(2(s))` is a non-polar molecular solid and is an insulator. `H_2O_((s))` is a hydrogen bonded molecular solid and is an insulator. Mg is metallic solid and is a conductor in solid as well as in molten state. TiO is an ionic solid and is an insulator in solid state but is a conductor in molten state and in aqueous solution . |
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| 140. |
The non-stoichiometric compound `Fe_0.94O` is formed when some `Fe^(+2)` ions are replaced by `Fe^(+3)` ions. What is the percentage of `Fe^(+3)` ions in this ionic lattice ?A. `18%`B. `25%`C. `13%`D. `6%` |
| Answer» Correct Answer - C | |
| 141. |
What type of stoichiometric defecit is shoen by ZnS ?A. Schottky defectB. Frenkel defectC. Both Frenkel and Schottky defectsD. Non-stoichiometric defect |
| Answer» Correct Answer - B | |
| 142. |
Schottky defect occurs mainly in electrovalent compounds whereA. Positive ions have large sizesB. Negative ions have small sizesC. Positive and negative ions are of similar sizeD. Positive ions are big and negative ions are small |
| Answer» Correct Answer - C | |
| 143. |
In the Schottky defect:A. an ion moves to interstitial position between the lattice pointsB. electrons are trapped in a lattice siteC. some lattice sites are vacantD. some extra cations are present in interstitial spaces |
| Answer» Correct Answer - C | |
| 144. |
How can you determine the atoic mass of an unknown metal if you know its density and the dimension of its unit cell ? Explain. |
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Answer» Let the edge length of a unit cell=a Density=d Molar mass=M Volume of the unit cell=a3 Mass of the unit cell =No. of atoms in unit cell xx Mass of each atom =Zxxm |
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| 145. |
Statement-1 :Schottky type of defect is shown by crystals with high co-ordination numbers . Statement-2 :In Schottky defect , equal number of cations and anions are missing from their lattice sitesA. 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 - B | |
| 146. |
What is meant by the term "coordination number"? b. What is the coordination number of atoms: i. in a cubic-packed structure? ii. In a body-centreds structure? |
| Answer» The number of nearest neighbours of a particle are called its coordination number (ii) (a) 12 (b) 8 | |
| 147. |
What is the two-dimensional coordination number of a molecule in square close-packed layer? |
| Answer» In 2D, square close-packed layer, an atom touches 4 nearest neighbouring atoms. Hence its CN=4 | |
| 148. |
which kind of defects are introduced by doping ?A. Dislocation defectsB. Schottky defectC. Frenkel defectsD. Electronic defects |
| Answer» Correct Answer - D | |
| 149. |
Statement-1:For NaCl structure, `Cl^-` ions occupy corners and face centre and `Na^+` ions occupy edge centres and body centre. Statement-2:The radius ratio of NaCl structure varies from 0.414 to 0.732A. 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 | |
| 150. |
Magnesium and Titanium form a crystalline oxide in which Mg appears at the eight corners , oxygen appears at face centres and titanium appears at the centre of cube. The atomic mass of magnesium , titanium and oxygen is 24, 45.9 and 16 amu respectively. A similar compound is formed by calcium with titanium and oxygen . What would be the molar mass of unit cell of `MgTiO_3` ?A. Nearly `118 "g mol"^(-1)`B. `"236 g mol"^(-1)`C. `"59 g mol"^(-1)`D. None of these |
| Answer» Correct Answer - A | |