Organic Analysis

Question 1

If the compound is acidic

Answer 1

Carboxylic acid

Question 2

If the compound dissolves in water

Answer 2

Suggests polar groups are present

Question 3

Test for alkenes

Answer 3

Shake with bromine water

Decolorises the solution (from orange)

Question 4

Test for halogenalkanes

Answer 4

1. Add NaOH (aq) and warm
2. Acidify with nitric acid
3. Add silver nitrate (aq)
   A precipitate of silver halide will form

Question 5

Test for alcohols

Answer 5

Add acidified potassium dichromate

Orange colour will turn green (if 1° or 2°)

Question 6

Test for aldehydes

Answer 6

1. Warm with Fehling’s solution; blue turns red

2. Warm with Tollen’s solution; silver mirror forms

Question 7

Test for carboxylic acids

Answer 7

Add sodium hydrogencarbonate (aq)

Carbon dioxide is produced

Question 8

Gas chromatography

Answer 8

Used to separate mixtures and measure the amounts of each component

Question 9

Infrared spectroscopy

Answer 9

Every bond has its own unique frequency

When a beam of IR radiation is shone through a sample, the bonds absorb radiation that has the same frequency

Question 10

The fingerprint region

Answer 10

The area of an infrared spectrum below about 1,500 cm^-1

Many peaks from complex vibrations, used to identify the chemical