How To Test For Negative Ions

The video tutorial explains how to test for carbonate, sulfate, and nitrate ions. For carbonates, dilute acid is added, and the gas produced is bubbled through lime water, turning it milky if carbonates are present. Sulfates are tested by adding barium chloride, forming a white precipitate. Nitrates are tested by adding sodium hydroxide and aluminum powder, producing ammonia, which turns damp litmus paper blue. The video emphasizes writing balanced chemical equations for these reactions.

What is the visual indication that carbon dioxide is produced when testing for carbonate ions?

• The solution bubbles vigorously.

• The solution turns blue.

• Lime water becomes milky.

• A red precipitate forms.

Which chemical is added to test for sulfate ions, resulting in a white precipitate?

• Magnesium sulfate

• Calcium carbonate

• Barium chloride

• Sodium chloride

What is the white precipitate formed when testing for sulfate ions?

• Barium sulfate

• Calcium sulfate

• Magnesium sulfate

• Sodium sulfate

What is the role of aluminum powder in the test for nitrate ions?

• It reduces nitrate ions to ammonium ions.

• It oxidizes nitrate ions.

• It acts as a catalyst.

• It neutralizes the solution.

How can the presence of ammonia be confirmed in the nitrate ion test?

• By the solution turning green.

• By the production of white smoke when exposed to hydrochloric acid.

• By the formation of a blue precipitate.

• By observing a color change to red on litmus paper.