Multiple Choice QuestionsA metal has a fcc lattice. The edge length of the unit cell is 404 pm. The density of the metal is 2.72 g cm3. The molar mass of the metal is (NA vogadro's constant = 6.02x 1023 mol-1).
40 g mol-1
30 g mol-1
27g mol-1
20 g mol-1
What is the co-ordination number of body centred cube ?
8
6
4
12
A.
8
The unit cell of body centred cube has 1 atom at each of the eight corners and 1 atom of the centre of the body. Thus, the atom at the centre remains in contact with 8 corners atoms. Hence, co-ordination number of bcc is 8.
A compound is formed by cation C and anion A. The anions form hexagonal close packed (hcp) lattice and the cations occupy 75% of octahedral voids. The formula of the compound is :
C3A2
C3A4
C4A3
C2A3
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