1. Which stoichiometric defect does not change the density of the crystal?
2. What type of stoichiometric defect is shown by AgCl?
3. What type of point defect is produced when AgCl is doped with CdCl2?
4. An element crystallises in a fcc lattice with cell edge of 250 pm. Calculate the density if 300 g of this element contains 2 × 10^24 atoms. (Ans – 38.4 gm/cm3)
5. The density of lead is 11.35 g cm–3 and crystallise with fcc unit cell. Estimate the radius of lead atom. (At. mass of lead = 207 g mol–1) (Ans – r = 174.95 pm)
6. An element occurs in bcc structure. It has a cell edge length of 250 pm. Calculate the molar mass if its density is 8.55 g cm–3. Also calculate the radius of an atom of this element. (Ans – 108 pm)
7. The density of copper metal is 8.95 g cm–3. If the radius of copper atom be 127.8 pm, is the copper unit cell simple cubic, body-centred cubic or face-centred cubic? (Given: atomic mass of Cu = 63.54 g mol–1) (Ans – 127.7 pm)
8. If NaCl is doped with 10–3 mole percent SrCl2, what will be the concentration of cation vacancies? (Ans - 6.023 × 10^18)
9. Zinc oxide on heating becomes yellow, why?
10. Why is Frenkel defects not found in pure alkali metal halides?