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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.
| 701. |
An ionic solid `"Lal"_(2)` shown electrical conduction due to presence ofA. `La^(2+) and 2l^(-)`B. `La^(3+), 2l^(-) and e^(-)`C. `La^(2+), I_(2) and 2e^(-)`D. `La^(3+), I_(2) and 3e^(-)` |
| Answer» Correct Answer - B | |
| 702. |
Crystalline solids have :A. GlassB. RubberC. PlasticD. Sugar. |
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Answer» Correct Answer - D Sugar is a crystalline solid while glass, rubber and plastic are amorphous solids. |
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| 703. |
Which type of solid crystals will conduct heat and electricity?A. lonicB. MetallicC. CovalentD. Molecular |
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Answer» Correct Answer - b Metallic crystal are good conductor of head and current due to free electrons in them . |
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| 704. |
Diamond is an exmaple of what kind of solid?A. Solid with hydrogen bondingB. Electrovalent solidC. Covalent solid.D. Glass. |
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Answer» Correct Answer - C Diamond is a covalent solid in which constituent particles are atoms. |
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| 705. |
The substance which does not show sharp melting point isA. KClB. GlassC. PlasticD. Diamond. |
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Answer» Correct Answer - B Amorphous or non-crystalline solids do not have sharp melting point. |
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| 706. |
Which type of solid crystals will conduct heat and electricity?A. IonicB. CovalentC. MetallicD. Molecular |
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Answer» Correct Answer - C Metallic crystals are good conductor of heat and current due to free electrons in them. |
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| 707. |
which of the following favours the existenence of a substance in the solid state ?A. High temperatureB. Low temperatureC. High thermal energyD. Weak cohesive forcs. |
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Answer» Correct Answer - B At sufficiently low temperature, the thermal energy is very low. The constituent particles are so close that they have hardly any translatory motion. The substances exist in the solid state. |
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| 708. |
Which of the following conditions favours the existence 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 |
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| 709. |
which of the following favours the existenence of a substance in the solid state ?A. High temperatureB. Low temperatureC. High thermal energyD. Weak choesive forces |
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Answer» Correct Answer - B At low temperature, molecular motion are slow, thus contituents are close together. Moreover , strong cohesive forces also holds the costituents together. These two conditions shows the existence of a substance in solid state. |
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| 710. |
In the time blende structure `(ZnS), S^(2-)` adopts ccp arrangement and `Zn^(2+)` occupiesA. Octahedral sitesB. Hexagonal sitesC. Teragonal sitesD. Both octahedral sites |
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Answer» Correct Answer - c Zine bleads (ZnS) has simple cubic arrangement so `Ze^(-2)` occupy tetrhedral sides. |
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| 711. |
The band formed atomic orbitals of lower energy is called….. While that formed from atomic orbitals of higher energy is called….. |
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Answer» Correct Answer - insulator |
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| 712. |
which of the following statement is correct for the `NaCl` lattice?A. An `Na^(+)` ion is placed at a distance of `(1)/(sqrt(2))a` directly above each `Cl^(-)` (where a is the cube unit cell edge length).B. An `Na^(+)` ion is placed at a distance of `(1)/(2sqrt(2))` a directly above each `Cl^(-)` ion.C. An `Na^(+)` ions is placed at a distance of `(1)/(6)a` directly above each `Cl^(-)` ionD. An `Na^(+)` ion is placed at a distance of `(1)/(2)a` directly above each `Cl^(-)`. |
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Answer» Correct Answer - 4 Simple ionic solids such a `NaCl` are like metals in that the individual ions are spheres that pack together in a regular way.However they differ from metals in that the spheres are not all the same size-anions are generally larger than cations . As a result ,ionic soilds adopt a variety fo different unit cells depending on the size and charge of the ions.`NaCl` has a face -centered cubic unit cell in which is the larger `CI^(-)` anions occupy corners and face centres , while the smaller `Na^(+)` cations fit into the octahedral holes between adjacent `CI^(-)` ions. |
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| 713. |
A compound `AB_(x)` is formed such that `A` atoms are at corners and `B` atoms at face centre. Find the value of `x`. |
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Answer» Correct Answer - 3 A atoms are at corners. `:. `No. of `A` atoms per unit cell `=8xx(1)/(8)=1` `B` atoms are face centre. `:. ` No. of `B` atoms per unit cell `=6xx(1)/(2)=3` `:. AB_(x)=Ab_(3) :. X=3` |
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| 714. |
What type of stoichiometric defect is shown by NaCl ? Explain. |
| Answer» Correct Answer - Schottky defect. | |
| 715. |
Write the three types of solids on the basis of their ability to conduct electric current. |
| Answer» Conductors, semi-conductors and insulators. | |
| 716. |
Statement`: 8:8` co`-` ordination of `CsCl` at low temperature changes to `6:6` co`-`ordinationat `760K`. Explanation`:` Temperature also infuences the strutures of solids. |
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Answer» Correct Answer - c |
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| 717. |
Statement `:` `6:6 co-` ordination at normal tempeature and pressure changes to `8:8` co`-` ordination at high pressure. Explanation `:` Pressure influences the structure of solids. |
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Answer» Correct Answer - c Explanation is correct reason for statement. |
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| 718. |
How will you convert CsCl structure into NaCl structure ? |
| Answer» By increasin temperature. | |
| 719. |
Ice crystallizes in hexagonal lattice. At the low temperature at which structure was determined, the lattice contents were were `a=4.53Å` and `c=7.41Å`. `c=741Å`. Calcuate the no. of `H_(2)O` molecules present in a unit cell. `(` Density of ice `=9.22g//cm)` |
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Answer» Correct Answer - 4 Volume of unit cell, `V=`Area of base `xx` Height `=2xx(sqrt(3))/(4)a^(2)xxc` `=(sqrt(3))/(2)xx(4.53xx10^(-8))xx7.41xx10^(-8)` ltbr. `=13.17xx10^(-23)cm^(3)` `:. ` Mass of unit cell `=Vxxrho=13.17xx10^(-23)xx0.92` `=1.21xx10^(-22)g` Let there are `n` effective water molecules in the given unit cell. Then `n` times the mass of each water molecule would be the mass of unit cell. `:. 1.21xx10^(-22)=nxx(8)/(6.023xx10^(23))` `:. n=4` |
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| 720. |
How many chloride ions are there around sodium ion in sodium.A. 3B. 8C. 4D. 6 |
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Answer» Correct Answer - D In NaCl crystal every `Na^(+)` ion is surrounded by 6 `Cl^(-)` ion and every chloride ion is surrounded by `6Na^(+)` ion. |
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| 721. |
The density of `Cr` atoms is `7.02g//cm`. If the unit cell has edge length `289p m`. Calculate the number of chromium atoms per unit cell. `(at ` masss of `Cr=52)`. |
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Answer» Correct Answer - 2 Density `rho=(zxxat. wt.)/(a^(3)xxN_(A))` `z=(rhoxxa^(3)xxN_(A))/(at.wt.)` `=(7.2xx(289xx10^(-10))^(3)xx6.023xx10^(23))/(52)` `:. n=2` |
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| 722. |
The crystal lattice of NaCl isA. face-centred cubic latticeB. Body-centred cubic latticeC. Simple cubic latticeD. Hexagonal close packing |
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Answer» Correct Answer - C |
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| 723. |
In `CsCl` with cubic structure, `Cl^(-)` ions are located at each corner and `Cs^(+)` ions at the centre of the unit cell. If `r_(Cs^(+))` and `r_(Cl^(-))` and `1.69Å` and `1.81Å` respectively. Find the value of edge length of cube. |
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Answer» Correct Answer - 4 `r_(Cs^(+))+r_(Cl^(-))=1.69+1.81=3.5Å` Diagonal length`=(asqrt(3))/(2)` `:. (asqrt(3))/(2)=3.5` or`a=(3.5xx2)/(sqrt(3))~~4` |
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| 724. |
Select right expression for determinig packing fraction (P.F.) of NaCl unit cell (assume ideal ) , if ions along an edge diagonal are absent :A. `P.F = ((4)/(3) pi(r_(+)^(3) + r_(-)^(3)))/(16sqrt2 r^(3))`B. `P.F = ((4)/(3) pi [(5)/(2) r_(+)^(3) + r_(-)^(3)])/(16 sqrt2 r_(-)^(3))`C. `P.F = ((4)/(3) pi [(5)/(2) r_(+)^(3) + r_(-)^(3)])/(16 sqrt2 r_(-)^(3))`D. `P.F = ((4)/(3) pi [(7)/(2) r_(+)^(3) + r_(-)^(3)])/(16 sqrt2 r_(-)^(3))` |
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Answer» Correct Answer - B Effective no. of `Na^(+)=4-(1+2xx(1)/(4))=(5)/(2)` Effective no. of `Cl^(-)=4sqrt(2)a=4r^(-)` P.F, `=("Vol. of effective no. of cations and anions")/("Vol. of unit cell")` |
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| 725. |
Select right expression for determinig packing fraction (P.F.) of NaCl unit cell (assume ideal ) , if ions along an edge diagonal are absent :A. `P.F.=((4)/(3)pi(r_(+)^(3)+r_(-)^(3)))/(16sqrt2 r_(-)^(3))`B. `P.F.=((5)/(2)pi(r_(+)^(3)+4r_(-)^(3)))/(16sqrt2 r_(-)^(3))`C. `P.F.=((4)/(3)pi((5)/(2)r_(+)^(3)+r_(-)^(3)))/(16sqrt2 r_(-)^(3))`D. `P.F.=((4)/(3)pi((7)/(2)r_(+)^(3)+r_(-)^(3)))/(16sqrt2 r_(-)^(3))` |
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Answer» Correct Answer - B |
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| 726. |
What is the coordination number of sodium in `Na_(2)O`A. 6B. 4C. 8D. 2 |
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Answer» Correct Answer - B In `Na_(2)O`, each oxide ions `(O^(2-))` is co-ordinated to `8 Na^(+)` ions and each `Na^(+)` ion to 4 oxide ions. Hence if has 4:8 co-ordination. |
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| 727. |
Find the coordination of `Na^(o+)` in `Na_(2)O`. |
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Answer» Correct Answer - 4 `Na_(2)O` has antifluorite structure. `O^(2-)` ions constitute `c.c.p.` lattice while `Na^(+)` ions occupy the tetrahedral voids. Each `O^(2-)` ions is in contact with `8Na^(+)` ions and each `Na^(+)` ions is nin contance with `4O^(2-)` ions . Thus the co`-` ordination number of sodium in `Na_(2)O` is 4. |
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| 728. |
What is the coordination number of sodium in sodium oxide ` ( Na_(2)O)` ?A. 6B. 4C. 8D. 2 |
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Answer» Correct Answer - B |
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| 729. |
Select right expression for determinig packing fraction (P.F.) of NaCl unit cell (assume ideal ) , if ions along an edge diagonal are absent :A. `((13)/(2)pir^(3)+(13)/(3)pir^(3))/(8(r_(+)-r_(-))^(3))`B. `((13)/(3)pir_(-)^(3)+(4)/(3)pir_(+)^(3))/(8(r_(+)r_(-))^(3))`C. `((16)/(3)pir_(-)^(3)+(13)/(3)pir_(+)^(3))/(8(r_(+)+r_(-))^(3))`D. `((4)/(3)pir_(-)^(3)+(13)/(3)pir_(+)^(3))/(8(r_(+)+r_(-))^(3))` |
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Answer» Correct Answer - 1 On face diagonal of NaCl, `3Cl^(-)` (2 corners+1 f.c) present. If ions along f.c. are removed `therefore` volume occupied `=[(8-2)xx(1)/(8)+(6-1)xx(1)/(2)](4)/(3)pir^(3)` `(6xx(1)/(5)+5xx(1)/(2))xx(4)/(3)pir^(3)=((3)/(4)+(5)/(2))xx(4)/(3)pir^(3)` `=((3+10)/(4))(4)/(3)pir^(3)=(13)/(4)xx(4)/(3)pir^(3)` |
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| 730. |
A bcc lattice is made up of hollow spheres of `B`. Spheres of solids `A` are present in hollow spheres of `B`. The radius of `A` is half of the radius of `B`. The ratio of total volume of spheres of `B` unoccupied by `A` in a unit cell and volume of unit cell is `A xx (pisqrt(3))/(64)`. Find the value of `A`. |
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Answer» Correct Answer - 7 Let radius of hollow sphere B=r `therefore` Edge length (a) `=4r//sqrt(3)` Volume of unit cell `=a^(3)=(4r//sqrt(3))^(2)` Volume of B unoccupied by A (having radius=r/2) in unit cell `=2xx[(4)/(3)pir^(3)-(4)/(3)pi((r)/(2))^(3)]` Volume of B unoccupied by A `therefore ("in unit cell")/("volume of unit cell")=`((4)/(3)pixx(7r^(3))/(3)xx2)/(((4r)/sqrt(3))^(3))=(7pisqrt(3))/(64)` `therefore Axx(7pisqrt(3))/(64)=(7pisqrt(3))/(64)` `therefore A=7` |
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| 731. |
Assertion : Stoichimetric compounds obey the law of constact composition Reason: Schottky and frenkel defect are observed in Stoichimetric compoundsA. If both assertion and reason are true and the reason is the correct explanation of the assertionB. If both assertion and reason are true but reason is not the correct explanation of the assertionC. If assertion is true bur reason is falseD. If assertion is false bur reason is true |
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Answer» Correct Answer - b In these defect stoichiomatry of compound is mainted |
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| 732. |
Assertion : `Na_(2)O` adopes structure similar to that of `CaF_(2)` but positions and negative ions are reversed Reason : The structure of`Na_(2)O` is also called spinal structureA. If both assertion and reason are true and the reason is the correct explanation of the assertionB. If both assertion and reason are true but reason is not the correct explanation of the assertionC. If assertion is true bur reason is falseD. If assertion is false bur reason is true |
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Answer» Correct Answer - c `Na_(2)O` structure is also known as antiflourite structure |
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| 733. |
Assertion : Solids having more F-centre possess intense colour Reason: Excess of `Na^(+)` in `NaCI` solid having F-centers makes it appear pinkA. If both assertion and reason are true and the reason is the correct explanation of the assertionB. If both assertion and reason are true but reason is not the correct explanation of the assertionC. If assertion is true bur reason is falseD. If assertion is false bur reason is true |
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Answer» Correct Answer - c Excese `Na^(+)` in `NaCI` solid in f-centre dropeds yellow colour |
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| 734. |
Assertion : Solids having more F-centre possess intense colour Reason: Excess of `Na^(+)` in `NaCI` solid having F-centers makes it appear pink |
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Answer» Correct Answer - a Excess of `Na^(+)` in `NaCl` solid at `F-` centres develops yellow colour. |
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| 735. |
Statement `:` The conductance through electrons is called `n-` type conductance and if through positive holes it is called `p-` type conducton. Explanation `:` Doping involves preparation of semi`-` conductors by the presence of impurities in the intrisic semi`-`conductor. |
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Answer» Correct Answer - d Both are facts. |
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| 736. |
Statement I: In any ionic solid `[MX]` with Schottky defect, the number of positive and negative ions are same. Statement II: An equal number of cation and anion vacancies is present. |
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Answer» Correct Answer - c Explanation is correct reason for statement. |
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| 737. |
Statement I: In any ionic solid `[MX]` with Schottky defect, the number of positive and negative ions are same. Statement II: An equal number of cation and anion vacancies is present.A. If both assertion and reason are correct and reason is correct explanation for assertionB. If both assertion and reason are correct but reason is not correct explanation for assertionC. If assertion is correct but reason is incorrectD. If both assertion and reason are incorrect |
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Answer» Correct Answer - A Reason is the correct explanation for assertion |
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| 738. |
Statement I: In any ionic solid `[MX]` with Schottky defect, the number of positive and negative ions are same. Statement II: An equal number of cation and anion vacancies is present.A. If both the statement are TRUE and STATEMENT -2 is the correct explanation of STATEMENT -1B.C. If STATEMENT -1 is the correcct and TRUE and STATEMENT -2 is FALSED. If STATEMENT -1 is the correcct and FALSE and STATEMENT -2 is TRUE |
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Answer» Correct Answer - A |
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| 739. |
`{:("Column I (Crystal)" , "Column II (Crystal system)"),("(A)" "CuSO"_(4).5 H_(2)O, "(p) Hexagonal"),("(B)" Na_(2)SO_(4).10 H_(2)O, "(q) Cubic"),("(C) Dimaond" , "(r) Monoclinic"),(" (D) Graphite" , "(s) Triclinic"):}`A. A-r,B-s, C-p, D-qB. A-s, B-r, C-q, D-pC. A-r,B-p , C-q , D-sD. A-p , B-q , C-r , D-s |
| Answer» Correct Answer - d | |
| 740. |
Graphite is a good conductor of eletricity due to the presence of …………….. .A. lone pair of electronsB. free valence electronsC. cationsD. anions |
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Answer» Correct Answer - B In graphite each C atom is `sp^(2)` hybridised. One electron of each C atom remains free and make graphite, a good conductor of electricity. |
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| 741. |
What is a semiconductor? Describe the two main types of semiconductor and contrast their conduction mechanism. |
| Answer» Substances whose conductances lies in between that of metals (conductors) and insulators are called semiconductors. Two main types of semiconductors are n-type and p-type | |
| 742. |
which of the following oxides behaves as conductor or insulator depending upon temperature ?A. `TiO`B. `SiO_(2)`C. `TiO_(3)`D. MgO. |
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Answer» Correct Answer - C `T_(2)O_(2)` can begave as conductor or insulator depending upon the temperature. |
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| 743. |
Write a feature which will distingulsh a metallic solid frojm an ionic solid ? |
| Answer» A metallic solid conducts electricity in the solid state wherease an ionic solid does not conduct electricity in the solid state but conducts only in the aquesous solution or molten state. | |
| 744. |
A solid `AB` has `NaCl` structure. If the radius of the cation `A` is `100` pm, what is the radius of anion `B`? |
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Answer» Correct Answer - `241 pm` In `NaCl`, it has `6 : 6 CN` `:.` It has `OV`. `:. r = (r_(ɵ))/(0.414) = (100)/(0.414) = 241` pm |
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| 745. |
A compound has cubical unit cell in which X atom are present at 6 corner, Y atom are at remaining corner & only at those face centres which are not opposite to each other & Z atoms are present at remaining face centre & body centre then find. (i) Formula of compound (ii) Density if edge length `= 2 Å` Given: Atomic mass of X = 40 amu, Y = 60 amu, Z = 80 amu |
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Answer» (i) `X = (1)/(8) xx 6 = (3)/(4)` `Y = (1)/(8) xx 2 + (1)/(2) xx 3 = (7)/(4)` `Z = (1)/(2) xx 3 + 1 + 1 = (5)/(2) = (10)/(4)` For formula: `X_(3) Y_(7) Z_(10) = X_(3) Y_(7) Z_(10)` (ii) 1 amu `= 1.67 xx 10^(-24)` gram 1 amu `= (1)/(6.02 xx 10^(23))` gram. Density `= ("Mass")/("Volume") = ((3)/(4) xx 40 + (7)/(4) xx 60 + (10)/(4) xx 80)/((2 xx 10^(-8))^(3))` amu/cc `= (335 xx 1.67 xx 10^(-24))/(8 xx 10^(-24)` = 69.8` gram/cc |
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| 746. |
A p-type material is electrically...A. positiveB. negativeC. neutralD. depends upon the concentration of p impurities |
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Answer» Correct Answer - C p-type material is electrically neutral |
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| 747. |
Cations are present in the intersitial sites in ……….A. frenkel defectB. Schottky defectC. Vacancy defectD. Metal deficiency defect |
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Answer» Correct Answer - B |
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| 748. |
In the fcc arrangement of `A` and `B` atoms whose `A` atoms are at corners of the unit cell and `B` are at the face centres one of the `A` atom is missing from one corner in each unit cell. What is the simplest formula of the compound? |
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Answer» Correct Answer - `A_(7)B_(24)` Corners share `= 7 xx (1)/(8) = (7)/(8)` Face centre share `= 6 xx (1)/(2) = 3` Formula: `A_(7//8)B_(3)` or `A_(7)B_(24)`. |
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| 749. |
In the face centered per unit cell, the lattice points are present at the:A. corners of unit cell onlyB. corners and centre of the unit cellC. corners and centre of each face of the unit cellD. face centres of the unit cell |
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Answer» Correct Answer - C |
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| 750. |
In the fcc arrangement of `A` and `B` atoms whose `A` atoms are at corners of the unit cell and `B` are at the face centres one of the `A` atom is missing from one corner in each unit cell. What is the simplest formula of the compound?A. `A_(7)B_(3)`B. `AB_(3)`C. `A_(7)B_(24)`D. `A_(2)B_(3)` |
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Answer» Correct Answer - C `A = 7 xx (1)/(8) = (1)/(8) , B = 6 xx (1)/(2) = 3` Formula `= A_(7//8) B_(3) " or " A_(7)B_(24)` |
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