1. Bisulfite or Hydrogen sulfite   SO4   Br   CO3   HSO3   Hint Half-n-half Clue   2. Bisulfate or Hydrogen sulfate   NO3   SO4   HSO3   HSO4   Half-n-half Clue   3. Nitrate   SO4   SO3   NO3   S   Half-n-half Clue   4. Oxide   SO3   NH4   OH   O   Half-n-half Clue   5. Bicarbonate or Hydrogen carbonate   HCO3   SO4   NO3   Cl   Half-n-half Clue   6. Carbonate   NO3   CO3   I   HCO3   Half-n-half Clue   7. Sulfate   O   SO4   I   PO4   Half-n-half Clue