Gus Paper

Topics: Crystal, Solid, Cubic crystal system Pages: 9 (2231 words) Published: September 3, 2010
Guess Paper – 2009
Class – XII
Subject –Chemistry : Solid State

(Q.1) The appearance of colour in solid alkali metal halides is generally due to: ( 1 mark ) (a) Frenkel defect(b) Interstitial positions(c) F-centres(d) Schottky effect

(Q.2) Schottky defects in crystal is observed when ( 1 mark )

(a) unequal number of cations and anions aremissing from the lattice(b) equal number of cations and anions are missing from the lattice(c) an ion leaves its normal siteand occupies an interstitial site(d) density of the crystal is increased

(Q.3) In an antiflourite structure, cations occupy: ( 1 mark ) (a) Octahedral voids(b) Centre of the cube(c) Tetrahedral voids(d) Corners of the cube

(Q.4) A p-typesemiconductor is electrically ( 1 mark )
(a) Negative(b) Positive(c) Neutral(d) Depends upon the concentration of impurities

(Q.5) Ferrimagnetism is shown by ( 1 mark )
(a) Nickel(b) Oxygen molecule(c) Cromium oxide (CrO2)(d) Magnetite

(Q.6) What are the stoichiometric defects found in ionic crystals? ( 1 mark )

(Q.7) Write two examples of amorphous solids? ( 1 mark )

(Q.8) A solid substance XY has a rock salt geometry. What is the co-ordination number of X and Y? How many atoms of X and Y are present in the unit cell? ( 1 mark )

(Q.9) What type of solids are malleable, ductile and electrical conductors? ( 1 mark )

(Q.10) How many atoms are present in the unit cell of bcc and fcc? ( 1 mark )

(Q.11) Sometimes,common salt is yellow instead of being pure white. Why? ( 1 mark )

(Q.12) What are voids?
( 1 mark )

(Q.13) What happens when ferrimagnetic Fe3O4 is heated to 850 K? ( 1 mark )

(Q.14) Name thepoint defect which lowers the density of a crystal. ( 1 mark )

(Q.15) What is the co-ordination number of Na+ and Cl- ions in NaCl structure? ( 1 mark )

(Q.16) What do you mean by F-center?
( 1 mark )

(Q.17) Name the type of solids which have long range orders. ( 1 mark )

(Q.18) Name one solid which has both Frenkel and Schottky defects? ( 1 mark )

(Q.19) Why is the window glass of the old building thick at the bottom? ( 1 mark )

(Q.20) What causes the conduction of electricity by semiconductors? ( 1 mark )

(Q.21) Which salt can be added to AgCl so as to produce cationic vacancies? ( 1 mark )

(Q.22) Define photovoltaic cell? ( 1 mark )

(Q.23) Name a transition metal oxide which has appreance and conductivity like that of Cu? ( 1 mark )

(Q.24) What is the co-ordination number of an atom present inoctahedral void? ( 1 mark )

(Q.25) Write one property which is caused due to the presence of F-center in a solid. ( 1 mark )

(Q.26) The crystal system of a compound with unit cell dimensions a=0.387, b=0.387 and c=0.504nm and α=β=900 and =1200 is: ( 1 mark )
(a) Cubic(b) Hexagonal(c) Orthorhombic(d) Rhombohedral

(Q.27) Which of the following is non-stoichiometric defect: ( 1 mark ) (a) Frenkel defect(b) Metal excess defect(c) Thermodynamic defect(d) Intrinsic defect

(Q.28) What is the coordination number of Cl- in NaCl crystal? ( 1 mark ) (a) 8(b) 6(c) 4(d) 3

(Q.29) On adding little phosphorous to silicon, we get a/an ( 1 mark ) (a) n-Type semiconductor(b) p-Type semiconductor(c) Metallic conductor(d) Insulator

(Q.30) A semiconductor of Ge can be made p-type by adding: ( 1 mark ) (a) Trivalent impurity(b) Tetravalent impurity(c) Pentavalent impurity(d) Divalent impurity

(Q.31) The electrical conductivity of semiconductors ( 1 mark ) (a) Increases with temperature(b) Decreases with temperature(c) Remains constant (d) Depends upon pressure

(Q.32) When molten zinc is cooled to solid state it assumes HCP structure. Then the number of nearest neighbours of zinc atom will be: ( 1 mark ) (a) 4(b) 6(c) 8(d) 12

(Q.33) Silicon can be converted into n-type semiconductor by adding impurityto it. Numberof valence electrons present in the impurity must be: ( 1 mark ) (a) 2(b) 5(c) 3(d) 1

(Q.34) In NaCl the chloride ions occupy the space in a fashion of: (...
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