1. Sulfate   SO4   I   HSO4   CO3   Hint Half-n-half Clue   2. Bicarbonate or Hydrogen carbonate   Br   PO4   S   HCO3   Half-n-half Clue   3. Bisulfite or Hydrogen sulfite   S   Cl   NO3   HSO3   Half-n-half Clue   4. Sulfide   PO4   NO3   I   S   Half-n-half Clue   5. Carbonate   NO3   CO3   HSO3   I   Half-n-half Clue   6. Chloride   HSO3   I   Cl   SO3   Half-n-half Clue   7. Hydroxide   HSO4   OH   Br   SO3   Half-n-half Clue