SrO is doped with 10-4 mol % of Sr+4 The concentration of created cation vacancies is NA × 10x per mol. Value of x is ________.

When one atom of Sr4+ replace Sr2+, to maintain electrical neutrality, one Sr2+ ion removes. Thus, the no. of cation vacancy will be equal to added SrO2 molecules.In one mole of the oxide, no. of moles of SrO2 added =10−5100=10−7No. of cation vacancies = 10−7× 6.023×1023=6.023×1016∴ x = 16