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1.	In a solid state AB having Nacl structure,A atoms occupy the corners of the cubic unit cell. If all the face centered atom along one of the axis are axis are removed the the resultant stoichiometry of the solid.. a)AB2 b)A2B c)A4B3 d) A3B4
Answer» According to NaCl structure so 'A' occupies 8 corners of the cubic unit cell which contribute 1/8 each to this cube therefore 81/8 = 1 also 6 face centered atoms contribute 1/2 to this cube therefore 61/2=3 Therefore total contribution of atom'A' is 4 Now B occupies octahedral voids(NaCl structure) which contribute 1/4 therefore 1+121/4 = 4 So the formula is A4B4 or AB Now you are removing all the face centered atoms along one axis(any axis origin at centre of cube) so the number of atoms removed from cube are 2 so contribution from 'A' remains 81/8(corner atoms) + 4*1/2(facecentered atoms) = 3 so the resultant becomes A3B4

In a solid state AB having Nacl structure,A atoms occupy the corners of the cubic unit cell. If all the face centered atom along one of the axis are axis are removed the the resultant stoichiometry of the solid.. a)AB2 b)A2B c)A4B3 d) A3B4

Answer»

According to NaCl structure

so 'A' occupies 8 corners of the cubic unit cell which contribute 1/8 each to this cube

therefore 8*1/8 = 1

also 6 face centered atoms contribute 1/2 to this cube

therefore 6*1/2=3

Therefore total contribution of atom'A' is 4

Now B occupies octahedral voids(NaCl structure) which contribute 1/4

therefore 1+12*1/4 = 4

So the formula is A4B4 or AB

Now you are removing all the face centered atoms along one axis(any axis origin at centre of cube)

so the number of atoms removed from cube are 2

so contribution from 'A' remains 8*1/8(corner atoms) + 4*1/2(facecentered atoms) = 3

so the resultant becomes A3B4

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