If is heavily doped with of , the concentration of cation vacancies created per mole is: — Solid State Chemistry Question

💡 Solution & Explanation

Each $Sr^{2+}$ replacing $Na^+$ creates one $Na^+$ vacancy for charge balance. $10^{-4}\text{ mol}\%$ means $10^{-6}$ mol dopant per mole of $NaCl$. Therefore vacancies per mole $=10^{-6}N_A=6.02\times10^{17}$.