Problem 70
In which of the following pairs the cations occupy same type of site (a) Zinc blende, \(\mathrm{Na}_{2} \mathrm{O}\) (b) \(\mathrm{NaCl}, \mathrm{CsCl}\) (c) \(\mathrm{Na}_{2} \mathrm{O}, \mathrm{CaF}_{2}\) (d) \(\mathrm{CsBr}, \mathrm{ZnS}\)
Problem 73
The radius ratio \(\left(\mathrm{r}^{+} / \mathrm{r}^{-}\right)\)of \(\mathrm{KF}\) is \(0.98\). The structure of \(\mathrm{KF}\) is similar to (a) \(\mathrm{NaCl}\) (b) \(\mathrm{CsCl}\) (c) \(\mathrm{ZnS}\) (d) both (a) and (b)
Problem 74
\(\mathrm{Na}_{2} \mathrm{O}\) has antifluorite structure. In \(\mathrm{Na}_{2} \mathrm{O}\), the coordination number of \(\mathrm{N}^{\mathrm{a}^{+}}\)and \(\mathrm{O}^{2}\) are respectively (a) 4,4 (b) 6,6 (c) 4,8 (d) 8,8
Problem 76
AB Crystallises in a B.C.C lattice with edge length. a as \(387 \mathrm{Pm}\). The distance between two oppositely charged ions in the lattice is (a) \(300 \mathrm{Pm}\) (b) \(335 \mathrm{Pm}\) (c) \(250 \mathrm{Pm}\) (d) \(200 \mathrm{Pm}\)
Problem 78
In calcium fluoride structure, the coordination numbers of calcium and fluoride ions respectively are (a) 6 and 8 (b) 8 and 8 (c) 4 and 8 (d) 8 and 4
Problem 79
In a body-centred cubic arrangement, A ions occupy the centre while \(\mathrm{B}\) ions occupy the corners of the cube. The formula of the solid is (a) \(\mathrm{AB}\) (b) \(\mathrm{AB}_{2}\) (c) \(\mathrm{A}_{2} \mathrm{~B}\) (d) \(\mathrm{AB}_{3}\)
Problem 80
If three elements A, B and C crystallized in cubic solid lattice with A atoms at corners, \(\mathrm{B}\) atoms at cube centres and \(\mathrm{C}\) atoms at the edges, the formula of the compound is (a) \(\mathrm{ABC}\) (b) \(\mathrm{ABC}_{3}\) (c) \(\mathrm{AB}_{3} \mathrm{C}\) (d) \(\mathrm{A}_{3} \mathrm{~B}_{2} \mathrm{C}_{3}\)
Problem 81
In a cubic unit cell, seven of the eight corners are occupied by atom \(\mathrm{A}\) and having of faces are occupied of \(\mathrm{B}\). The general formula of the substance having this type structure would be (a) \(\mathrm{A}_{7} \mathrm{~B}_{14}\) (b) \(\mathrm{A}_{14} \mathrm{~B}_{7}\) (c) \(\mathrm{A}_{7} \mathrm{~B}_{24}\) (d) \(\mathrm{A}_{9} \mathrm{~B}_{24}\)
Problem 82
If the anions (b) form hexagonal close packing and cations (a) occupy only \(2 / 3\) octahedral holes in it, then the general formula of the compound is (a) \(\mathrm{AB}_{2}\) (b) \(\mathrm{A}_{2} \mathrm{~B}_{3}\) (c) \(\mathrm{A}_{3} \overrightarrow{\mathrm{B}}_{3}\) (d) \(\mathrm{A}_{2} \mathrm{~B}_{2}\)
Problem 83
In a spinel structure, oxides ions are cubical closest packed, whereas \(1 / 8\) of tetrahedral holes are occupied by cations \(\mathrm{A}^{2}\) and \(1 / 2\) of octahedral holes are occupied by cations \(\mathrm{B}^{3+}\) ions. The general formula of the compound having spinel structure is (a) \(\mathrm{AB}_{2} \mathrm{O}_{4}\) (b) \(\mathrm{A}_{2} \mathrm{~B}_{2} \mathrm{O}_{4}\) (c) \(\mathrm{A}_{2} \mathrm{~B}_{6} \mathrm{O}\) (d) \(\mathrm{A}_{4} \mathrm{~B}_{3} \mathrm{O}\)
