• # question_answer $N{{a}_{2}}C{{O}_{3}}$ cannot be used in place of ${{(N{{H}_{4}})}_{2}}C{{O}_{3}}$ for the identification of $C{{a}^{2+}},B{{a}^{2+}}$ and $S{{r}^{2+}}$ ions because A)  Concentration of $CO_{3}^{2-}$ ions is very lowB)  $N{{a}^{+}}$ ions will interfere with the detection of $C{{a}^{2+}},B{{a}^{2+}}$ and $S{{r}^{2+}}$C)  Sodium will react with acid radicals.D)  Magnesium will be precipitated.

$N{{a}_{2}}C{{O}_{3}}$ is completely dissociated to $N{{a}^{+}}$ and $CO_{3}^{2-}$ ions thus giving high concentration of $CO_{3}^{2-}$ ions which would precipitate $M{{g}^{2+}}$ as $MgC{{O}_{3}}$.