Practical Work

Question 1

Test for ammonium ions

Answer 1

• React the salt with sodium hydroxide solution in a test tube
• Warm gently
• Test gas produced with damp red litmus paper
  If positive - Litmus paper turns blue

Question 2

How can you distinguish between group two cations?

Answer 2

Using sulfuric acid and sodium hydroxide, as the solubility of group two sulfates and hydroxides varies down the group.
(Alternatively - flame tests)

Question 3

Flame test for calcium

Answer 3

Brick red

Question 4

Flame test for strontium

Answer 4

Red

Question 5

Flame test for barium

Answer 5

Pale green

Question 6

Test for hydroxide ions in aqueous solution

Answer 6

• Add universal indicator to the test solution
  If positive - colourless solution turns blue

Question 7

Test for carbonate ions in aqueous solution

Answer 7

• Add equal volumes of test solution and dilute HCl in a test tube
• Collect gas produced with a pipette
• Test gas with lime water
  If positive - lime water turns cloudy

Question 8

Test for sulfate ions in aqueous solution

Answer 8

• Add equal volumes of test solution and dilute HCl in a test tube
• Add an equal volume of barium chloride solution
  If positive - white precipitate forms

Question 9

What is lime water?

Answer 9

An aqueous solution of calcium hydroxide

Question 10

Test for water

Answer 10

Cobalt chloride paper
Colour change from blue to pink