Organic Synthesis And Analysis

Question 0

What are the different reducing agents you need to know and what do each of them reduce?

Answer 0

NaBH4: C=O
H2/Ni: C=C
Sn/H+: R-NO2 to R-NH2

Question 1

What is the main oxidising agent you need to know?

Answer 1

Acidified K2Cr2O7

Question 2

How can alcohols be converted to alkenes?

Answer 2

Passing their vapours over heated aluminium oxide or by acid catalysed elimination reactions

Question 3

How can we synthesise propanoic acid starting with 1-bromopropane

Answer 3

1-bromopropane undergoes Nucleophilic substitution using NaOH to form propan-1-ol propan-1-ol then gets oxidised using K2Cr2O7/H+

Question 4

How can we synthesise propylamine starting with ethene?

Answer 4

Firstly ethene undergoes electrophilic addition with HBr to form
bromo-ethane which then undergoes Nucleophilic substitution with KCN to form propanenitrile which must then be reduced with Ni/H2

Question 5

What is the test and positive result for an alkene

Answer 5

Shake with bromine water and the red brown colour dissapears

Question 6

What is the test and positive result for haloalkanes?

Answer 6

Add NaOH and heat, acidify with HNO3 then add AgNO3 and it should form a precipitate of AgX

Question 7

What is the test and the positive result for alcohols?

Answer 7

Acidified K2Cr2O7. Orange turns green with primary or secondary alcohols but also with aldehydes

Question 8

What is the test and positive result for aldehydes?

Answer 8

Warm with fehling’s or tollen’s solution. Blue wil turn brick red precipitate or a silver mirror will form

Question 9

What is the test and positive result for carboxylic acids?

Answer 9

Add NaOHCO3 and CO2 will be given off

Question 10

What is the test and positive result for acyl chlorides?

Answer 10

Add AgNO3 and there will be a vigorous reaction, white precipitate will be formed.