Let us calculate the molecular formula of NaOH. Mol Wt of Na is 23g/mol, O is 16g/mol and H is 1g/mol. Therefore, mol wt of NaOH is 23+16+1 = 40 g/mol or 40 grams in 1 mole. Now according to Avogadro's constant, 1 mole of any substance contains 6.023 * 10^23 ions/molecules. Thus, 40 gm of NaOH will contain 6.023*10^23 ions of Na. So, 80 gm of NaOH will have [(6.023*10^23) / 40]*80 = 12.046*10^23 ions of Na. Thus, 80 grams of NaOH will contain 12.046*10^23 ions of Na.