6.3 ANALYSIS

Question 1

Test for alkenes?

Answer 1

Reagents = bromine water
Observation = add few drops of bromine water, shake
Result = orange to colourless

Question 2

Test for haloalkanes?

Answer 2

Reagents = aqueous silver nitrate and ethanol
Observation = add reagents
Result =

Question 3

Test for carbonyl compounds?

Answer 3

Reagents = 2,4- DNP (bradys reagent)
Observation = add reagent
Result = orange percipitate forms

Question 4

Test for aldehydes?

Answer 4

Reagents = tollens reagent
Observation = add reagent
Result = silver mirror coating forms

Question 5

Test for alcohols?

Answer 5

Reagents = acidified potassium dichromate
Observation = distill for primary alcohols, then excess reagent and strong reflux for primary alcohols, reflux for secondary alcohols
Result = colour change from orange to green

Question 6

Test for phenols?

Answer 6

Reagents = carbonate ion and pH probe
Observation = check pH is that of a weak acid, add carbonate ion
Result = no effervesence, no reaction with carbonate ion

Question 7

Test for aliphatic carboxylic acids?

Answer 7

Reagents = reactive metal/metal carbonate and pH probe
Observation = check pH is that of a weak acid, add reactive metal
Result = effervensence produced as carboxylic acid reacts

Question 8

What is the stationary phase in thin-layer chromatography?

Answer 8

• Metal/glass covered in absorbant chemical (aluminum oxide/silicone dioxide)

Question 9

What is the mobile phase in thin-layer chromatography?

Answer 9

• An organic liquid solvent

Question 10

Rf value equation?

Answer 10

Question 11

What is the stationary phase in gas chromatography?

Answer 11

• A solid/liquid coating on a coiled tube

Question 12

What is the mobile phase in gas chromatography?

Answer 12

• An unreactive carrier gas

Question 13

In a gas chromatography chart, what does the area under the peaks show?

Answer 13

• The relative concentration of that chemical in the mixture

Question 14

What is TMS used for in NMR spectroscopy

Answer 14

• an internal standard for carbon and proton NMR chemical shift

Question 15

Describe what deuterium is

Answer 15

• An isotope of hydrogen that does not produce signals on a proton NMR as it doesnt contains protons

Question 16

State the two deuterium solvents

Answer 16

• CDCl3
• D2O

Question 17

Explain the use of the deuterium solvent CDCl3

Answer 17

• Used as a solvent

Question 18

Explain the use of the deuterium solvent D2O

Answer 18

• Used to identify OH and NH protons by exchanging protons so that their signals do not show up when D2O is shook vigerously in sample

Question 19

What does the number of peaks/signals show on carbon/proton NMR

Answer 19

• the number of different environments

Question 20

What does the peak splitting on signals of proton NMR show?

Answer 20

• the number of hydrogen atoms on adjacent carbon atoms
• (n+1)

Question 21

What does the number above the signals on proton NMR show?

Answer 21

• the number of hydrogen atoms in that environment