If NaCl is doped with 1/100 mol% of SrCl2, what is the concentration of cationic vacancies?

If NaCl is doped with 10^(-2) mol% SrCl_(2) , what is the concentration of the cation vacancies?

If NaCl is doped with 10^(-1)mol% of SrCl_(2) ,the concentration of cation vacancies will be "

If NaCl is doped with 10^(-4)mol% of SrCl_(2) the concentration of cation vacancies will be (N_(A)=6.02xx10^(23)mol^(-1))