What’s in a medicine

Question 1

What is a carbonyl group?

Answer 1

A functional group with a C=O double bond that is polar with trigonal planar geometry (~120°).

Question 2

What is the structure of a phenol?

Answer 2

C6H5OH, with additional groups optionally attached.

Question 3

What is the general formula of aldehydes?

Answer 3

RCHO, where R represents an alkyl group.

Question 4

What is the general formula of ketones?

Answer 4

-C(O)- or -CO-, with R and R’ as alkyl groups.

Question 5

What is the general formula of acid anhydrides?

Answer 5

(RCO)2O.

Question 6

What is the general formula of esters?

Answer 6

RCOOR’.

Question 7

What is the general formula of carboxylic acids?

Answer 7

RCOOH, containing a carboxyl group (-COOH).

Question 8

What is the general formula of ethers?

Answer 8

ROR’, where the oxygen is bonded to two alkyl groups.

Question 9

What distinguishes primary alcohols?

Answer 9

The -OH group is bonded to a carbon atom attached to only one other carbon atom.

Question 10

What distinguishes secondary alcohols?

Answer 10

The -OH group is bonded to a carbon atom attached to two other carbon atoms.

Question 11

What distinguishes tertiary alcohols?

Answer 11

The -OH group is bonded to a carbon atom attached to three other carbon atoms.

Question 12

How do phenols differ from alcohols?

Answer 12

Phenols are aromatic, and the -OH group is not connected to an alkane.

Question 13

What is the reaction of phenol with sodium hydroxide?

Answer 13

Phenol + NaOH → Sodium phenoxide + Water.

Question 14

Why don’t phenols react with carbonates?

Answer 14

Phenols are not strong enough acids to react with carbonates.

Question 15

What happens when neutral FeCl3 is added to phenol?

Answer 15

It forms a purple solution due to the formation of an iron(III) complex.

Question 16

How are esters formed using phenols?

Answer 16

Phenols react with acid anhydrides, not carboxylic acids, to form esters.

Question 17

What is esterification?

Answer 17

A reaction between an alcohol and a carboxylic acid in the presence of an acid catalyst to form an ester and water.

Question 18

What is the role of acid anhydrides in ester formation?

Answer 18

They react with alcohols to form esters and carboxylic acids.

Question 19

What happens when primary alcohols are oxidised?

Answer 19

They form aldehydes with distillation or carboxylic acids with reflux.

Question 20

What happens when secondary alcohols are oxidised?

Answer 20

They form ketones, which cannot be oxidised further.

Question 21

Why can’t tertiary alcohols be oxidised?

Answer 21

The carbon atom with the -OH group is not bonded to a hydrogen atom that can be removed.

Question 22

What is the dehydration of alcohols?

Answer 22

An elimination reaction where alcohols lose H2O to form alkenes.

Question 23

How are haloalkanes made from alcohols?

Answer 23

React alcohols with halide acids (e.g., HCl) to substitute the -OH group with a halogen.

Question 24

What is heating under reflux used for?

Answer 24

To prevent the loss of volatile or flammable substances during a reaction.

Question 25

What are the steps to purify an organic liquid product?

Answer 25

Use a separating funnel, neutralise impurities, dry with anhydrous salt, and distill.

Question 26

How is water removed from a purified product?

Answer 26

Add an anhydrous salt like MgSO4 until the liquid stops being lumpy, then filter.

Question 27

What is the process of recrystallisation?

Answer 27

Dissolve a solid in hot solvent, cool to form crystals, filter, and dry the product.

Question 28

What is thin-layer chromatography (TLC) used for?

Answer 28

To separate and identify small quantities of organic compounds.

Question 29

What is vacuum filtration used for?

Answer 29

To separate a solid from a filtrate using a vacuum pump and Buchner funnel.

Question 30

How is melting point used to assess purity?

Answer 30

Pure substances have a sharp melting range, while impurities increase the range.

Question 31

What is the synthesis of aspirin?

Answer 31

Hydrolyse methyl-2-hydroxybenzoate, esterify salicylic acid with ethanoic anhydride, and recrystallise the product.

Question 32

What is green chemistry?

Answer 32

A sustainable approach to reduce waste, use safer chemicals, lower energy usage, and prevent environmental damage.

Question 33

What does mass spectroscopy measure?

Answer 33

The molecular ion peak (M⁺) shows the molecular mass, and fragmentation patterns identify molecular components.

Question 34

What does IR spectroscopy measure?

Answer 34

The absorption of IR radiation by covalent bonds, indicating specific functional groups.

Question 35

What are the main IR regions?

Answer 35

4000–2500 cm⁻¹ (hydrogen bonds), 2500–2000 cm⁻¹ (triple bonds), 2000–1500 cm⁻¹ (double bonds).

Question 36

What is the fingerprint region in IR spectroscopy?

Answer 36

The region below 1500 cm⁻¹ used to identify unique compounds.