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question_answer1) What are fluids?
question_answer2) What is the cause of rigidity in solids?
question_answer3) What kind of attractive forces are present in the molecular solids?
question_answer4) What kind of attractive forces are present in the ionic solids?
question_answer5) What kind of attractive forces are present in the covalent solid?
question_answer6) What kind of attractive forces are present in the metallic solids?
question_answer7) Are ionic solids electrical conductors or insulators?
question_answer8) What are pseudo solids?
question_answer9) What is isotropy?
question_answer10) What is anisotropy?
question_answer11) Which type of solids have sharp melting point?
question_answer12) Which type of solids have definite enthalpy of fusion?
question_answer13) Which type of solids have long range ordered arrangement of constituent particles?
question_answer14) What is photovoltaic materials? Give example.
question_answer15) Which type of intermolecular force is present in non-polar molecular solids?
question_answer16) Which type of intermolecular force is present in polar molecular solids?
question_answer17) Which type of intermolecular force is present in ice?
question_answer18) Which type of solids are hard and brittle?
question_answer19) Which type of solids are soft and brittle?
question_answer20) Which type of solids are called giant molecules?
question_answer21) Which type of motion is possible in solid particles?
question_answer22) Which property of glass enables it to be moulded and blown into various shapes?
question_answer23) What is a unit cell?
question_answer24) Define space lattice.
question_answer25) What are primitive and non-primitive unit cells?
question_answer26) How many atoms are present per unit cell of primitive cubic unit cell?
question_answer27) How many atoms per unit cell are present in (i) body centred and (ii) face centred cubic unit oell?
question_answer28) What is the co-ordination number of each lattice point in hexagonal close pack structure? [Delhi 2005]
question_answer29) What is the co-ordination number in the body centred cubic close packed structure?
question_answer30) What is the co-ordination number in the cubic close packed (face centred-cubic) structure?
question_answer31) What is total number of atoms per unit cell present in hexagonal close packed arrangement?
question_answer32) Which type of voids are present in a solid crystal?
question_answer33) What is the radius ratio value for tetrahedral void?
question_answer34) What is the maximum radius of a sphere that can be filled in the tetrahedral void of cubic close packing of spheres of radius R without disturbing it?
question_answer35) What is the ratio between radius of a sphere (R) and the radius of the octahedral void (r) in the cubic close packing?
question_answer36) What is the coordination number of octahedral voids?
question_answer37) What is the range of radius ratio (r/R) value in tetrahedral coordination? [AI 1997]
question_answer38) What is the range of radius ratio (rlR) value for octahedral co-ordination? [AI 1997 C]
question_answer39) What is the number of octahedral and tetrahedral voids per unit cell of cubic close packing (fee)?
question_answer40) What happens to a sodium chloride structure when high pressure is applied to it?
question_answer41) What happens to a caesium chloride structure when high temperature is applied to it? [Delhi 1998 C]
question_answer42) What is the name of unit cell in which atoms are placed at the corners of all 12 edges of a cubic unit cell?
question_answer43) Silver halide forms crystals similar to NaCl. Under what condition these changes to CsCI crystals?
question_answer44) Name the type of structure of CsCI.
question_answer45) What do you mean by imperfections in solid?
question_answer46) What is point defect?
question_answer47) What is Frenkel defect?
question_answer48) What is Schottky defect?
question_answer49) Which point defect lowers density of solid? [AI 2000, Delhi 2004]
question_answer50) What type of compounds exhibit Schottky defect?
question_answer51) What is the effect on the density of a crystal due to Schottky defect?
question_answer52) Name a compound in which Frenkel and Schottky defect are present together.
question_answer53) Why is the Frenkel defect not found in pure alkali metal halides?
question_answer54) Zinc oxide is white but becomes yellow-on heating. Why?
question_answer55) NaCl crystals when heated in sodium vapours become yeltew Why?
question_answer56) KCl crystals when heated in potassium vapours become violet Why?
question_answer57) What are F centres?
question_answer58) Why there is no change in density of a solid due to Frenkel defect?
question_answer59) Mention one property which is caused due to the presence of F centres [2003]
question_answer60) Name a salt that can be added to AgCl so as to produce cation vacancy.
question_answer61) What are ferromagnetic substances?
question_answer62) What is doping? Why is it done?
question_answer63) What may be the difference between phosphorus doped and gallium doped semiconductors.
question_answer64) Although pure silicon is an insulator, how does it behave as a semiconductor on heating? [Delhi 1997]
question_answer65) What causes the conduction of electricity by semiconductors? [CBSE Sample Paper 1997]
question_answer66) What other element may be added to silicon to make electrons available for conduction of an electric current? [Delhi 2001]
question_answer67) What is the effect of temperature on conduction of semi conductors?
question_answer68) How is ferromagnetism difCereaffl-om paramagnetism?
question_answer69) Define ferrimagnetism.
question_answer70) What happens when ferrimagnetic is heated at 850 K and Why? [AI 2004]
question_answer71) Solid solution of group-13 or group-15 impurities with group-14 elements are found to exhibit unusual electric properties. Why?
question_answer72) What is mean by (i) 12 - 16 compounds and (ii) 13-15 compounds. Give examples.
question_answer73) Why is ferrimagnetic at room temperature but becomes conductor at 850 K?
question_answer74) How do electrical conductivity of following class of materials vary with temperature? (i) Semiconductor (ii) Metallic conductor (iii) Super conductor.
question_answer75) Explain the following terms : (a) Ferrimagnetism (b) n-type semiconductor (c) Forbidden zone.
question_answer76) The following two graphs represent conductivity as function of temperature. Predict giving reasons, the type of substances which will show these types of curves.
question_answer77) What are the properties offerromagnets. Give an example offerromagnet.
question_answer78) Cubic solid is made of two elements X and Y. Atoms of Y are at the corners of the cube and X at the body centre. What is the formula of compound? [AI 2006]
question_answer79) Why do solids have definite volume as well as shape?
question_answer80) What are crystalline solids?
question_answer81) Define the term amorphous.
question_answer82) Why are amorphous solids called pseudo solids or super cooled liquids?
question_answer83) Crystalline solids are anisotropic. Why?
question_answer84) Amorphous solids are isotropic. Why?
question_answer85) Metallic solids are conductors of heat and electricity. Why?
question_answer86) How a given material can be made amorphous?
question_answer87) Why is graphite used as lubricant?
question_answer88) Graphite is conductor of electricity. Given reasons.
question_answer89) Why is diamond extremely hard and insulator?
question_answer90) Ionic solids are insulator of heat and electricity. Why?
question_answer91) Molecular solids are soft and brittle. Explain.
question_answer92) Why glass panes fixed to windows or doors of old buildings are found to be thicker at the bottom?
question_answer93) Some glass objects from ancient civilisations are found to become milky in appearance. Explain. [Delhi 2000]
question_answer94) What is a void? Name any two voids.
question_answer95) What is meant by co-ordination number in a solid?
question_answer96) Define radius ratio.
question_answer97) What is the length of the side of unit cell if the radius of an element which crystallises in a body centred cubic lattice is 75 pm?
question_answer98) How will you differentiate between bcc and fee lattice?
question_answer99) How will you differentiate between hcp and ccp lattice?
question_answer100) If the radius ofanion in an ionic solids is 100 pm, what should be the radius of cation that fits in the (a) cubic hole, (b) octahedral hole, (c) tetrahedral hole?
question_answer101) What is the effect of Frenkel defect on electrical conductivity of solid? [AI 2003]
question_answer102) What types of defect is produced when Nad is doped with ?
question_answer103) Name the non-stoichiometric point defects responsible for colour in alkali halides. [AI 2006]
question_answer104) Schottky defects generate an equal number of cation and anion vacancies while doping produces only cation vacancies and not anion vacancies. Why?
question_answer105) Give two reasons of crystal imperfections.
question_answer106) State the difference between Schottky and Frenkel defects.
question_answer107) Which of the two changes the density of solid?
question_answer108) What makes alkali metal halides sometimes coloured which are otherwise colourless? [Delhi 2004]
question_answer109) ] What are the solids? What are their characteristics?
question_answer110) What are amorphous and crystalline solids? Give example of each type.
question_answer111) How are crystalline solids classified? Give example of each type.
question_answer112) What are ionic solids? What are their characteristics?
question_answer113) What are metallic solids? What are their characteristics?
question_answer114) What are covalent solids and what are their characteristics?
question_answer115) What are molecular solids? What are the characteristics of various types of molecular solids?
question_answer116) What are structural differences between graphite and diamond?
question_answer117) What are the differences between ionic and metallic solids?
question_answer118) What are the differences between covalent and molecular solids?
question_answer119) What are the differences between crystalline and amorphous solids?
question_answer120) Energy is needed when a solid at its melting point is converted into a liquid. Why?
question_answer121) Urea has a sharp melting point but glass does not. Explain.
question_answer122) Why is latent heat of fusion of solid carbon dioxide less than that of silicon dioxide?
question_answer123) What is the difference between London dispersion forces and dipole-depole forces?
question_answer124) Distinguish between crystal lattice and unit cell.
question_answer125) Classify the following into \[n\]-type and \[p\]-type semiconductors and assign suitable explanation. (i) Ge doped with In (ii) B doped with Si.
question_answer126) Gas lighter when pressed produces flame. Explain.
question_answer127) Ferromagnetic and ferrimagnetic substances become paramagnetic upon heating. Discuss.
question_answer128) The electrical conductivity of a metal decreases with rise in temperature while that of semi-conductor increases. Justify
question_answer129) \[CaC{{l}_{2}}\] will introduce schottky defect if added to \[AgCl\] crystal. Explain.
question_answer130) Why is common salt sometimes yellow instead of being white?
question_answer131) Why are defects in the crystalline solids called thermodynamic defects?
question_answer132) Addition of \[CdC{{l}_{2}}\] to the crystals of \[AgCl,\] will produce Schottky defects but the same is not produced when NaCI crystals are added. Discuss.
question_answer133) Cesium chloride is more stable than sodium chloride. Assign reason.
question_answer134) Why is diffusion in solids less as compared to the liquids?
question_answer135) How will you show that glass is a super cooled liquid?
question_answer136) The melting point of sodium chloride is more than that of sodium. Justify.
question_answer137) The ions of NaF and MgO have the same number of electrons and inter nuclear 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)?
question_answer138) \[AgI\] crystallizes in a cubic close-packed ZnS structure. What fraction of tetrahedral sites is occupied by\[A{{g}^{+}}\]ions?
question_answer139) Crystals possessing \[CsCl\] structure change to NaCI structure upon heating. Give a suitable explanation.
question_answer140) Why does zinc oxide which is white in colour become yellow upon heating?
question_answer141) Schottky defect lowers the density of ionic crystals while Frenkel defect does not. Discuss.
question_answer142) A metallic element crystallises into a lattice containing sequence of layers AB AB AB....... Any packing of spheres leaves out voids in the lattice. What percentage by volume of this lattice is empty space?
question_answer143) What difference in behaviour between glass and sodium chloride would you expect to observe if you break off a piece of either cube?
question_answer144) Frenkel defect is not found in the halides of alkali metals. Assign reason.
question_answer145) The ions of NaF and MgO have the same number of electrons and inter nuclear 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 2642C)?
question_answer146) What difference in behaviour between glass and sodium chloride would you expect to observe if you break off a piece of either cube?
question_answer147) A metallic element crystallises into a lattice containing sequence of layers AB AB AB....... Any packing of spheres leaves out voids in the lattice. What percentage by volume of this lattice is empty space?
question_answer148) Schottky defect lowers the density of ionic crystals while Frenkel defect does not. Discuss.
question_answer149) Why does zinc oxide which is white in colour become yellow upon heating?
question_answer150) Crystals possessing \[CsCl\] structure change to NaCI structure upon heating. Give a suitable explanation.
question_answer151) \[AgI\] crystallizes in a cubic close-packed ZnS structure. What fraction of tetrahedral sites is occupied by\[A{{g}^{+}}\]ions?
question_answer152) The ions of NaF and MgO have the same number of electrons and inter nuclear 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)?
question_answer153) The melting point of sodium chloride is more than that of sodium. Justify.
question_answer154) How will you show that glass is a super cooled liquid?
question_answer155) Why is diffusion in solids less as compared to the liquids?
question_answer156) Energy is needed when a solid at its melting point is converted into a liquid. Why?
question_answer157) Urea has a sharp melting point but glass does not. Explain.
question_answer158) Why is latent heat of fusion of solid carbon dioxide less than that of silicon dioxide?
question_answer159) Cesium chloride is more stable than sodium chloride. Assign reason.
question_answer160) produce Schottky defects but the same is not produced when NaCI crystals are added. Discuss.
question_answer161) Why are defects in the crystalline solids called thermodynamic defects?
question_answer162) Why is common salt sometimes yellow instead of being white?
question_answer163) \[CaC{{l}_{2}}\] will introduce schottky defect if added to \[AgCl\] crystal. Explain.
question_answer164) The electrical conductivity of a metal decreases with rise in temperature while that of semi-conductor increases. Justify
question_answer165) Ferromagnetic and ferrimagnetic substances become paramagnetic upon heating. Discuss.
question_answer166) Gas lighter when pressed produces flame. Explain.
question_answer167) Classify the following into \[n\]-type and \[p\]-type semiconductors and assign suitable explanation. Ge doped with In (ii) B doped with Si.
question_answer168) Distinguish between crystal lattice and unit cell.
question_answer169) What is the difference between London dispersion forces and dipole-depole forces?
question_answer170) What is the difference between London dispersion forces and dipole-depole forces?
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