3.1.4: Qualitative analysis

Question 1

Give the sequence that chemical tests should be carried out in

Answer 1

Carbonate → Sulfate → Bromide

Question 2

Give the test to identify ammonium ions (NH4+)

Answer 2

Heat gently with NaOH and ph paper will turn blue as the solution becomes more alkaline as NH3 forms which turns damp red pH paper blue

Question 3

Give test for hydroxide ions

Answer 3

Turns damp red litmus blue

Question 4

Give the test for carbonate ions

Answer 4

• React with HCl
• CO2 gas produced which turns limewater cloudy when bubbled through

Question 5

Give the test for sulfate ions

Answer 5

• Add HCl to remove carbonates which could precipitate
• Add barium chloride, BaCl2
• White precipitate forms (INSOLUBLE)

Question 6

Give the ionic equation for the sulfate ion test

Answer 6

Ba2+ (aq) + SO42- (aq) —–> BaSO4 (s)

Question 7

Give the ionic equation for the ammonium ion test

Answer 7

NH4+ +OH- —> NH3 + H20

Question 8

Give the test for halide ions

Answer 8

• Add dilute nitric acid (HN03) to react with anions
• Add a few drops of silver nitrate solution (AgNO3)

Question 9

Give the result for chloride ions in silver nitrate (include equation) and when ammonia added to precipitate

Answer 9

• White precipitate
  Ag+ + Cl- —> AgCl
• Dissolves in dilute NH3

Question 10

Give the result for bromide ions in silver nitrate (include equation) and when ammonia added to precipitate

Answer 10

• Cream precipitate
  Ag+ + Br- —> AgBr
• Dissolves in concentrated NH3

Question 11

Give the result for iodide ions in silver nitrate (include equation) and when ammonia added to precipitate

Answer 11

• Yellow precipitate
  Ag+ + I- —> AgI
• Insoluble in concentrated NH3

Question 12

Give ionic equation for carbonate test

Answer 12

2H+ + CO3 2– → CO2 + H2O

Question 13

Name the apparatus used to separate 2 liquid layers

Answer 13

Separating funnel

Question 14

How could you speed up the rate of hydrolysis of haloalkanes

Answer 14

Heat the test tubes in a water bath.