Problem 96
Which of the following statements is correct? (1) The coordination number of each type of ion in CsCl crystal is 8 (2) A metal that crystallizes in BCC structure has a coordination number of 12 (3) A unit cell of an ionic crystal shares some of its ion with other units cells (4) the length of unit cell in \(\mathrm{NaCl}\) is \(552 \mathrm{pm}\) (r \(\mathrm{Na}^{+}=\) \(\left.95 \mathrm{pm}, \mathrm{r} \mathrm{Cl}^{-}=181 \mathrm{pm}\right)\) (a) 1,2 (b) 1,3 (c) 2,3 (d) 2,4
Problem 97
The edge length of the unit cell of \(\mathrm{NaCl}\) crystal lattice is \(552 \mathrm{pm}\). If the ionic radius of sodium ion is \(95 \mathrm{pm}\). What is the ionic radius of chloride ion? (a) \(181 \mathrm{pm}\) (b) \(190 \mathrm{pm}\) (c) \(276 \mathrm{pm}\) (d) \(368 \mathrm{pm}\)
Problem 99
The closet distance between two atoms (in terms of edge length) would be highest for which of unit cell, assuming the edge length of each unit cell of be 'a' (a) FCC unit cell (b) BCC unit cell (c) diamond unit cell (d) primitive cubic cell
Problem 102
A solid XY has \(\mathrm{NaCl}\) structure. If radius of \(\mathrm{X}^{+}\)is 100 \(\mathrm{pm}\), the radius of \(\mathrm{Y}\) - ion is (a) \(136.6\) to \(241.6 \mathrm{pm}\) (b) \(341.6\) to \(134.6 \mathrm{pm}\) (c) \(128 \mathrm{pm}\) (d) \(136.8 \mathrm{pm}\)
Problem 103
The ionic radii of \(\mathrm{Rb}^{+}\)and \(\mathrm{I}^{-}\)are \(1.46 \AA\) and \(2.16 \AA\) respectively. The most probable type of structure exhibited by it is (a) \(\mathrm{CaF}_{2}\) type (b) \(\mathrm{ZnS}\) type (c) \(\mathrm{CsCl}\) type (d) \(\mathrm{NaCl}\) type
Problem 104
A solid has 3 types of atoms namely X, Y and Z. X forms an FCC lattice with \(\mathrm{Y}\) atoms occupying all the tetrahedral voids and \(\mathrm{Z}\) atoms occupying half the octahedral voids. The formula of the solid is (a) XYZ (b) \(\mathrm{X}_{2} \mathrm{Y}_{4} \mathrm{Z}\) (c) \(\mathrm{X}_{4} \mathrm{YZ}_{2}\) (d) \(\mathrm{X}_{4} \mathrm{Y}_{2} \mathrm{Z}\)
Problem 105
Calculate the \(\lambda\) of X-rays which give a diffraction angle \(2 \theta=16.80^{\circ}\) for a crystal. (Given interplanar distance \(=\) \(0.200 \mathrm{~nm} ;\) diffraction \(=\) first order; \(\sin 8.40^{\circ}=0.1461\) ) (a) \(58.4 \mathrm{pm}\) (b) \(5.84 \mathrm{pm}\) (c) \(584 \mathrm{pm}\) (d) \(648 \mathrm{pm}\)
Problem 107
In a compound \(\mathrm{XY}\), the ionic radii \(\mathrm{X}^{+}\)and \(\mathrm{Y}\) are \(88 \mathrm{pm}\) and \(200 \mathrm{pm}\) respectively. What is the coordination number of \(\mathrm{X}^{+}\)? (a) 4 (b) 6 (c) 8 (d) 10
Problem 108
The edge length of unit cell of a metal having molecular weight \(75 \mathrm{~g} / \mathrm{mol}\) is \(5 \AA\) which crystallizes in cubic lattice. If the density is \(2 \mathrm{~g} / \mathrm{cc}\) then find the radius of metal atom. \(\left(\mathrm{NA}=6 \times 10^{23}\right)\). Give the answer in \(\mathrm{pm}\). (a) \(116.5 \mathrm{pm}\) (b) \(316.5 \mathrm{pm}\) (c) \(216.5 \mathrm{pm}\) (d) \(416.5 \mathrm{pm}\)
Problem 109
Sodium metal crystallizes as a body-centred cubic lattice with the cell edge \(4.29 \AA\). What is the radius of sodium atom? (a) \(2.371 \times 10^{-7} \mathrm{~cm}\) (b) \(1.857 \times 10^{-8} \mathrm{~cm}\) (c) \(3.817 \times 10^{-8} \mathrm{~cm}\) (d) \(7.312 \times 10^{-7} \mathrm{~cm}\)
