Testing for Metal Ions and Ammonium Ion

This lesson covers testing for transition and non-transition metal ions, as well as the ammonium ion. It explains the use of flame tests for Group 1 and 2 metals and copper ions, and the addition of sodium hydroxide to identify transition metals by the color of the precipitate formed. The oxidation of iron(II) hydroxide to iron(III) hydroxide is discussed, along with tests for non-transition metals like calcium, aluminum, and magnesium. The lesson concludes with methods to test for ammonium ions by detecting ammonia.

Which test is used to identify Group 1 and Group 2 metal ions?

• Oxidation test

• Precipitation test

• Flame test

• Litmus test

What color precipitate is formed when copper(II) ions react with sodium hydroxide?

• Blue

• Green

• White

• Reddish brown

What happens to iron(II) hydroxide when it stands for a while?

• It remains green

• It turns blue

• It dissolves

• It turns reddish brown

Why does iron(II) hydroxide change color upon standing?

• It reacts with water

• It reacts with air

• It oxidizes to iron(III) hydroxide

• It decomposes

Which metal ion forms a white precipitate with sodium hydroxide?

• Zinc

• Iron(III)

• Copper(II)

• Iron(II)

What flame color is associated with calcium ions?

• Green

• Brick red

• No color

• Blue

What is the color of zinc hydroxide precipitate?

• Green

• Blue

• Reddish brown

• White

How can the presence of ammonium ions be detected?

• By the formation of a blue precipitate

• By the formation of a white smoke

• By the change of red litmus paper to blue

• By the change of blue litmus paper to red

What is formed when ammonium ions react with sodium hydroxide?

• Ammonia

• Hydrochloric acid

• Oxygen

• Water

Which method can be used to confirm the presence of ammonia gas?

• Using a thermometer

• Using a blue litmus paper

• Using a glass rod dipped in hydrochloric acid

• Using a flame test