KCET 2019 Chemistry Solved Paper

(C)
1 mol SrCl2 gives 1 cationic vacancy.
10−5 moles of SrCl2 gives 10−5 mole cationic vacancies.
∴ The number of cationic vacancy in 1 moles of NaCl when it is doped with 10−5 moles of SrCl2 is 6.022 × 1018 .