Chemistry Practicals

Question 1

Sweet fruity smell

Answer 1

• Ester

Question 2

Yellow or blue non-sooty flame

Answer 2

• Aliphatic compound with low carbon content

Question 3

Yellow sooty flame

Answer 3

• Aromatic compound of high carbon content

Question 4

Organic compound miscible in water

Answer 4

• Polar aliphatic compound of low molecular mass

Question 5

Organic compound partially/ sparingly miscible in water

Answer 5

• Polar aliphatic compound of high molecular mass

Question 6

Organic compound immiscible in water

Answer 6

• Non-Polar organic compound of low molecular mass

Question 7

Organic compound turned damp blue litmus paper red

Answer 7

• Acidic organic compound

Question 8

Organic compound turned damp red litmus paper blue

Answer 8

• Basic organic compound

Question 9

Organic compound had no effect on red or blue litmus paper

Answer 9

• Neutral organic compound

Question 10

Organic compound dissolved in dilute sodium hydroxide without effervescence

Answer 10

• Carboxylic acid
• Phenol

Question 11

Organic compound formed bubbles of a gas with sodium carbonate or sodium hydrogen carbonate solution

Answer 11

Carboxylic acid

Question 12

Organic compound formed a yellow precipitate with 2,4-dinitrophenylhydrazine

Answer 12

• Carbonyl compound

Question 13

Organic compound formed a sweet fruity smell when added to ethanoic acid in presence of concentrated sulphuric acid

Answer 13

Ester formed; alcohol present

Question 14

Organic compound formed a sweet fruity smell when added to ethanol in presence of concentrated sulphuric acid

Answer 14

Ester formed; carboxylic acid present

Question 15

Organic compound formed a purple solution with neutral iron(iii) chloride solution

Answer 15

Phenol

Question 16

Organic compound formed a brown precipitate with neutral iron(iii) chloride solution

Answer 16

• Benzoic acid
• carboxylic acid

Question 17

Organic compound formed a white precipitate with sodium hydroxide solution and silver nitrate solution

Answer 17

Chloroalkane

Question 18

Organic compound formed a cream precipitate with sodium hydroxide solution and silver nitrate solution

Answer 18

Bromoalkane

Question 19

Organic compound formed a yellow precipitate with sodium hydroxide solution and silver nitrate solution

Answer 19

Iodoalkane

Question 20

Organic compound turned a brown solution of bromine water colourless

Answer 20

Unsaturated compound eg
alkyne, alkene

Question 21

• Organic compound turned a brown solution of bromine water to a white precipitate

Answer 21

Unsaturated compound
eg Aromatic amine, phenol

Question 22

Organic compound turned a purple solution of potassium permanganate to a colourless solution

Answer 22

(Reducing agent)
- Primary alcohol
- Secondary Alcohol
- Aldehyde
- Methanoic acid

Question 23

Organic compound turned an orange solution of potassium dichromate solution to a green solution

Answer 23

• Primary alcohol
• Secondary Alcohol
• Aldehyde
• Methanoic acid

Question 24

Organic compound formed a silver mirror with ammoniacal silver nitrate solution

Answer 24

• Aldehyde
• Methanoic acid
  (It is a mild oxidizing agent)

Question 25

Organic compound formed a reddish brown precipitate with Fehling’s solution/ ammoniacal copper(I) chloride

Answer 25

- Aldehyde (except benzaldehyde) - Methanoic acid (It is a mild oxidizing agent)

Question 26

- Organic compound formed a white precipitate/ colourless crystals with sodium hydrogen sulphite

Answer 26

- Methyl ketone - Aldehyde (other than methanal and ethanal)

Question 27

Organic compound formed a cloudy solution immediately with anhydrous zinc chloride and concentrated hydrochloric acid solution (Lucas’ reagent)

Answer 27

Tertiary alcohol

Question 28

Organic compound formed a cloudy solution in 7 minutes with anhydrous zinc chloride and concentrated hydrochloric acid solution (Lucas’ reagent)

Answer 28

Secondary alcohol

Question 29

Organic compound; no cloudy solution with anhydrous zinc chloride and concentrated hydrochloric acid solution (Lucas’ reagent)

Answer 29

Primary alcohol

Question 30

Organic compound formed yellow precipitate with iodine and sodium hydroxide solution

Answer 30

- Secondary alcohol with the structure - Ethanol (only primary alcohol with the structure) - Ketone with the structure - Ethanal (only aldehyde with the structure)

Question 31

Crystalline compound

Answer 31

- Sulphates - Nitrates - Chlorides - Oxalates - Sulphite - Ethanoate

Question 32

Powdery compound

Answer 32

- Carbonates - Oxides

Question 33

White solid, colourless solution

Answer 33

Non-transition element ions - Zinc - Aluminum - Lead - Tin - Ammonium - Calcium - Barium - Magnesium

Question 34

Black solid

Answer 34

- Oxide - Sulphide Of a transition metal

Question 35

Green solid, green solution

Answer 35

- Chromium ions - Iron(ii) ions - Copper(ii) ions - Nickel(ii) ions

Question 36

Blue solid, blue solution

Answer 36

- Copper(ii) ions

Question 37

Yellow solid, yellow solution

Answer 37

- Chromium(vi) ions from chromate ions - Iron(iii) ions

Question 38

Orange solid, orange solution

Answer 38

- Chromium(vi) ions from dichromate ions

Question 39

Pale pink, not visible in solution

Answer 39

Manganese(ii) ions

Question 40

Brown solid, brown solution

Answer 40

Iron(iii) ions

Question 41

Pale violet solid, pale violet solution

Answer 41

Chromium(iii) ions

Question 42

Red or pink solid, solution

Answer 42

- Cobalt(ii) ions - Manganese(ii) ions

Question 43

White to reddish brown residue on heating which turned yellow on cooling

Answer 43

- PbO formed, Pb2+ present

Question 44

White to yellow residue when hot, turned yellow on cooling

Answer 44

ZnO formed, Zn2+ formed