Organic tests

Question 1

test for alcohol (metal)

Answer 1

add metalic sodium, hydrogen gas given if squeaky pop test

Question 2

test for alcohol (K₂Cr₂O₇) method

Answer 2

add acidified K₂Cr₂O₇
Primary and secondary alcohols will go from ORANGE to GREEN
(orange dichromate(VI) into green chromium(III)

No change if a tertiary alcohol

Question 3

Test for Aldehyde

Answer 3

Mix Fehling’s A + B → dark blue solution.
add aldehyde, heat in hot water.

Brick red precipitate = aldehyde present.
No visible change = Ketone

Question 4

Test for Alkene

Answer 4

1cm^3 Bromine water added to 2 drops of the supposed Alkene

Alkene will turn the orange bromine water colourless when shaken vigorously

Question 5

Test for carboxylic acid

Answer 5

Add ethanoic acid to sodium carbonate.
Bubble gas into limewater.
Limewater turns cloudy = CO₂ = carboxylic acid present.
Phenols don’t react (not acidic enough).

Question 6

Test for Halogenoalkane

Answer 6

• Add 1-bromobutane to NaOH → heat (nucleophilic substitution).
• Acidify with HNO₃, then add AgNO₃. (to remove hydroxide and carbonate impurities
• White/cream ppt = silver bromide formed (Br⁻ replaced).