1. Bisulfate or Hydrogen sulfate   CO3   NH4   SO4   HSO4   Hint Half-n-half Clue   2. Chloride   S   Cl   SO3   I   Half-n-half Clue   3. Ammonium   NH4   HSO4   OH   Br   Half-n-half Clue   4. Carbonate   OH   I   CO3   HSO4   Half-n-half Clue   5. Phosphate   HSO4   S   Cl   PO4   Half-n-half Clue   6. Oxide   HSO3   O   NH4   SO3   Half-n-half Clue   7. Sulfite   CO3   SO3   I   HCO3   Half-n-half Clue