1. Distinguishing between organic compounds
Organic substances can look the same – you must be able to distinguish between common compounds by comparing their properties and performing simple tests.
12 Chemistry organic chemistry CR 07

2. Common compounds Alcohols, carboxylic acids, alkanes, alkenes, esters
- all colourless liquids!
How could you distinguish between them??
12 Chemistry organic chemistry CR 07

3. Alcohols, carboxylic acids, alkanes, alkenes, esters
Questions you could ask:
Is it flammable?
Is it miscible with water?
Does it react with an oxidant?
Does it react with halogens?
Does it smell?
Does it behave as an acid?
12 Chemistry organic chemistry CR 07

4. Alcohols, carboxylic acids, alkanes, alkenes, esters
Mix with water
Miscible
Not miscible
- 2 layers
Alcohol (short chain)
Carboxylic acid
Alkane
Alkene
Ester
12 Chemistry organic chemistry CR 07

5. Alcohols, carboxylic acids, alkanes, alkenes, esters
Add magnesium
Reaction
No reaction
Carboxylic acid
Fizzing and litmus will go pink
Alkane
Alkene
Ester
Alcohol
12 Chemistry organic chemistry CR 07

6. Alcohols, carboxylic acids, alkanes, alkenes, esters
Add Br2
Reaction
orange 
No reaction
Alkane slow –requires UV light
Alkene fast – no catalyst required
Carboxylic acid
Ester
Alcohol
clear
12 Chemistry organic chemistry CR 07

7. Alcohols, carboxylic acids, alkanes, alkenes, esters
Add Cr2O72-/H+
Reaction
orange  green
No reaction
Alcohol for primary alcohols
Carboxylic acid
Ester
Alkene
Alkane
12 Chemistry organic chemistry CR 07

8. Alcohols, carboxylic acids, alkanes, alkenes, esters
Carefully smell
Fruity smell
Not fruity
Ester
* Carboxylic acid may smell unpleasant
Carboxylic acid
Alkene
Alkane
Alcohol
12 Chemistry organic chemistry CR 07

9. Alcohols, carboxylic acids, alkanes, alkenes, esters
Carefully ignite – not necessary as other tests will identify them
flammable
Not flammable
Ester volatile
Alkene sooty orange
flame
Alkane clean burning
Alcohol clean burning
Carboxylic acid
12 Chemistry organic chemistry CR 07