11.6 Water Purification

• What purification method is used to purify seawater in the video?

  Distillation
• What does the term "potable water" mean?

  Water that is safe to drink
• How is sodium tested in seawater?

  Using a flame test
• What color flame indicates the presence of sodium ions?

  Bright yellow flame
• What is the negatively charged ion produced from a chlorine atom gaining an electron?

  Chloride ion
• What method is used to test for chloride ions in seawater?

  Precipitation reaction
• What two chemicals are added to test for chloride ions?

  Nitric acid and silver nitrate
• What is produced when silver ions react with chloride ions?

  Insoluble silver chloride precipitate
• What is the purpose of distillation in this process?

  To separate water from sodium and chloride ions
• What happens to the water during distillation?

  It evaporates and then condenses back into liquid water
• What is the term used for the water collected after distillation?

  Distillate
• Why is a clean nichrome wire used for the flame test after distillation?

  To avoid contamination from previous tests
• What result indicates that sodium ions are no longer present after distillation?

  No yellow flame during the flame test
• What was the result of the chloride ion test after distillation?

  No white precipitate formed
• What is the role of nitric acid in the chloride ion test?

  To prevent interference from other ions
• How does the distillation process ensure the removal of sodium and chloride ions from seawater?

  By boiling the water and allowing it to evaporate, leaving the ions behind