THE STURDY STATE
CONCERNS VSA CONCERNS (1 - MARK QUESTIONS)
1 . 2 . 3. 4. 8. on the lookout for. What are anistropic substances. How come amorphous hues isotropic in nature? Why glass is certainly an shadowy solid? Establish the term 'crystal lattice. ' Define the word voids. What type of stochiometric defect is shown by (i) ZnS and (ii) CsCl? [Hint.: (i) Frenkel defect (ii) Schottky defect] *10. If the mixture of a substance is A2B, which sites would be filled by A ions? [Hint.: Number of A ions is definitely double to B ions, so ions will inhabit tetrahedral voids] 11. What is the coordination number for (a) (b) a great octahedral void a tetrahedral void.
[Hint.: (a) 6; (b) 4 ] *12. How various octahedral voids are there in 1 gopher of a mixture having cu closed jam-packed structure? [Ans.: you mole] 13. Arrange simple cubic, bcc and fcc lattice in reducing order in the fraction of the unoccupied space. [Hint.: fcc < bcc < sc] 14. How much space is vacant in a hexagonal closed jam-packed solid?
XII вЂ“ Chemistry
A feature crystallises independently both in hcp and ccp structure. Will the two buildings have the same density? Justify the answer. [Hint: The two crystal structures have same density because the percentage of occupied space is same. ]
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In NaCl amazingly, ClвЂ“ ions form the cubic close providing. What sites are filled by Na+ ions. In Corundum, O2вЂ“ ions coming from hcp and Al3+ occupy two third of octahedral voids. Identify the mixture of corundum. [Ans.: Al2O3] How come Frenkel defect not found in pure alkalinity metal halides? Which level defect is definitely observed in a crystal if a vacancy is made by an atom absent from a lattice web page. Define the term вЂdoping'. How come conductivity of silicon enhance with the rise in temperature. Name the crystal defect which usually lowers the density associated with an ionic very. [Ans.: Schottky defect]
What makes the crystal of KCl sometimes appear purple? [Hint: F-Centre]
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Which point defect in ionic crystal does not alter the density of the relevant solid? Name one stable in which both equally Frenkel and Schottky defects occur. Which type of defects are known as thermodynamic defects? [Ans.: Stoichiometric defects]
In a p-type semiconductor the current is said to move through holes. Describe. Solid A is very hard, electrical insulator in stable as well as in molten state and melts for extremely high temperature. What type of solid is it? [Hint: Covalent solid]
XII вЂ“ Hormone balance
SA (I) TYPE QUESTIONS (2 - DRAW QUESTIONS)
1 ) 2 . List four variations between crystalline and shadowy solids with one example of every. Give ideal reason for the followingвЂ“ (a) (b) 3. 4. your five. Ionic solids are hard and fragile. Copper is malleable and ductile.
Define FвЂ“centre. Point out its one particular consequence. What is packing productivity. Calculate the packing efficiency in body-centered cubic crystal. Explain: (a) (b) List two differences between metallic and ionic crystals. Sodium chloride is hard but sodium metal is usually soft.
Account for the subsequent: (a) (b) Glass objects from ancient civilizations are normally found to become milky in appearance. Window glass window panes of old buildings are thicker in the bottom than at the top.
Why is graphite soft lube and very good conductor of electricity? So what do you understand by following types of putting sequences: (a) AB AB............... (b) A B CABC.................
What kind of lattices do these sequences lead to? on the lookout for. Derive the formula to get the thickness of a very whose entire edge with the unit cell is known?
пЈ® zm пЈ№ пЈЇ *Hint: d = 3 пЈє a Г— nA пЈ» пЈ°
twelve. Explain just how much portion of an atom is located at (a) corner (b) body hub (c) face-centre and (d) edge center of a cu unit cellular.
*11. In a fcc arrangement of A and B atoms A are present at the sides of the device cell and B are present at the encounter centres. If one atom of A is missing from the position on the corner,...