Advertisements
Advertisements
Question
If NaCl is doped with 10−3 mol % of SrCl2, what is the concentration of cation vacancies?
Advertisements
Solution
When NaCl is doped with SrCl2, each additional Sr2+ ion eliminates two Na+ ions, creating two vacancies, one occupied by Sr2+ and the other unoccupied. Thus, adding one Sr2+ ion results in one cation vacancy.
Doping of NaCl with 1 × 10−3 rnol % of SrCl2 means that 1 × 10−3 moles of NaCl are added to 100 moles of NaCl.
∴ 1 mole of NaCl contains SrCl2 = `(1 xx 10^-3)/100`
= 1 × 10−5 moles
= 1 × 10−5 × 6.022 × 1023 molecules
= 6.022 × 1018 molecules
∴ No. of Sr2+ ions present in one mole of NaCl = No. of cation vacancies in one mole of NaCl
= 6.022 × 1018
APPEARS IN
RELATED QUESTIONS
Explain the following term with a suitable example:
F-centres
Yellow colour of NaCl crystals in sodium vapour is due to ____________.
The following diagram shows:
Which of the following will have metal deficiency defect?
Which of the following is a non-stoichiometric defect?
Pink colour of LiCl crystals is due to ______.
Why does table salt, NaCl, sometimes appear yellow in colour?
Why does white ZnO (s) becomes yellow upon heating?
Match the types of defect given in Column I with the statement given in Column II.
| Column I | Column II |
| (i) Impurity defect | (a) NaCl with anionic sites called F-centres |
| (ii) Metal excess defect | (b) FeO with Fe3+ |
| (iii) Metal deficiency defect | (c) NaCl with Sr2+ and some cationic sites vacant |
A sample of ferrous oxide has actual formula Fe0.93O1.00. In this sample what fraction of metal ions are Fe2+ ions? What type of nonstoichiometric defect is present in this sample?
The appearance of colour in solid alkali metal halides is generally due to ______.
On doping Ge metal with a little of In (indium), we get:
The non-stoichiometric compound Fe0 940 is formed when x% of Fe2+ ions are replaced by as many `2/3` Fe3+ ions. The value of x is
Non-stoichiometric defects refer to ______
