Question

CARBON AND ITS COMPOUNDS

What are primary and secondary suffixes as applied to IUPAC nomenclature?

Answer 1

The primary suffix indicates if the carbon chain is saturated or unsaturated.

TYPE OF CARBON CHAIN PRIMARY SUFFIX GENERAL NAME

Saturated. -ane. Alkane

Unsaturated with one double bond -ene. Alkene

Unsaturated with one triple bond. -yne Alkyne

The secondary suffix indicates the nature of the functional group present in an organic compound.

COMPOUND. FUNCTIONAL GROUP. SECONDARY SUFFIX

Alcohols -OH -ol

Aldehyde -CHO -al

Ketones. >C=O. -one

Carboxylic acids. -COOH. -oic acid

Answer 2

The primary and secondary suffix play an important role in Nomenclature.

√ There are three components of an IUPAC name.

• root word
• primary suffix
• secondary suffix

The root word example meth , eth , but depends on the number of carbon atoms in the compound.

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Primary suffix

• Depends upon the present of single,double or triple bonds
• A one bonded compound is ended with -ane
• A double bonded compound is ended with -ene
• A triple bonded compound is ended with -yne

A single bonded organic compound is called alkane

Example : methane , ethane ,propane

A double bonded organic compound is called alkene

Example : ethene , propene [ methene does not exist can you guess why? ]

A triple bonded compound is called alkyne

Example : ethyne , propyne [ methyne does not exist ]

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Secondary suffix

• This depends upon the presence of functional groups

Alcohols

They have OH group of atoms . The secondary suffix is -ol .

Examples :

• CH 3 - OH  is called methanol
• CH 3 - C H 2 - OH is called ethanol

Aldehydes

They have a double bond of O and another bond with H .Their secondary suffix is -al

Examples:-

• H-CHO is called methanal
• H 3 C - CHO is called ethanal

Note that all aldehydes begin from the compound.No aldehyde can be present in the middle of the compound.

Carboxylic acids

They have a double bond of O and another bond with OH .Their secondary suffix is -oic acid

Examples:-

• CH 3 - COOH is called methanoic acid
• CH3- CH 2 - COOH is called ethanoic acid

Note that all carboxylic acids begin from the compound.No acid can be present in the middle of the compound.

Ketones

Ketones have double bond O only .

This can only be present in the middle unlike aldehydes

Examples:

• CH 3- O - CH -3 is propanone or 2-propanone
• CH 3 - CO - C 2 H 5 is butanone 2 - butanone

Alkyl halides

Bromo contains Br atoms and Chloro contains Cl atoms

Examples :

• CH 3 Cl is choro methane
• CH 3 Br is bromo methane

Hope it helps you

You can ask your doubts if you have any

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