1. H2O   sodium hydroxide   potassium nitrate   sodium chloride   water   Hint Hint       2. CuSO4   copper sulfate   magnesium oxide   sodium chloride   potassium hydroxide   Hint       3. CO2   carbon disulfide   carbon dioxide   potassium nitrate   sodium hydroxide   Hint       4. SO2   sulfur dioxide   sodium chloride   carbon disulfide   hydrogen peroxide   Hint       5. KOH   sodium carbonate   potassium hydroxide   sulfur dioxide   potassium permanganate   Hint       6. MgO   hydrochloric acid   carbon disulfide   magnesium oxide   sulfur dioxide   Hint       7. KNO3   nitric acid   ammonium sulfate   potassium hydroxide   potassium nitrate   Hint