Identification Of Ions

Question 1

How to test for positive ions (cations)?

Answer 1

By flame tests and precipitation reactions

Question 2

What are flame tests used for?

Answer 2

Flame tests can be used to identify some metal ions (cations)

Question 3

What color flame does lithium have?

Answer 3

Crimson red

Question 4

What color flame does sodium have?

Answer 4

Yellow

Question 5

What color flame does potassium have?

Answer 5

Lilac

Question 6

What color flame does calcium have?

Answer 6

Orange red

Question 7

What color flame does copper have?

Answer 7

Green

Question 8

What do you use for precipitation reactions?

Answer 8

Sodium hydroxide solution

Question 9

How can sodium hydroxide solution identify some metal ions?

Answer 9

Sodium hydroxide is added to a solution of the metal ion to be tested, a solid precipitate (often colored) is formed and can be used to identify the metal ion

Question 10

What color precipitate do aluminum, calcium and magnesium ions form?

Answer 10

Aluminum, calcium and magnesium ions form white precipitate when sodium hydroxide solution is added, but only the aluminum hydroxide precipitate dissolves in excess sodium hydroxide solution.

Question 11

What color precipitates does copper Il, iron Il and iron Ill form?

Answer 11

• Copper Il ions form a blue precipitate
• Iron Il ions form a green precipitate . Iron Ill ions form a brown precipitate when sodium hydroxide solution is added

Question 12

How to identify halide ions?

Answer 12

Halide ions in a solution produce precipitate with silver nitrate solution in the presence of dilute nitric acid.

Question 13

What color precipitate do these halide ions produce? Silver chloride, silver bromide and silver iodide

Answer 13

• Silver chloride is white
• Silver bromide is cream
• Silver iodide is yellow