Organic Chemistry – Some Basic Principles Part 1

Section: Chemistry

Question : 71 of 100

Marks: +1, -0

The correct decreasing order of priority for the functional groups of organic compounds in the IUPAC system of nomenclature is

[AIEEE 2008]

−COOH,−SO3H,−CONH2,−CHO
−SO3H,−COOH,−CONH2,−CHO
−CHO,−COOH,−SO3H1−CONH2
−CONH2,−CHO,−SO3H,−COOH

Validate

Solution:

The correct order of priority for the given functional group is

−COOH>−SO3H>−

−NH2>−

−H

Functional group (priority order)

suffix(s)

prefix

(1)

−

−OH
(Carboxylic acid)

Oic acid(when carbon(C) of this functional group present in the main chain)or
Carboxylic acid (when carbon(C) of this functional group is not present in the main chain)

Carboxy

(2)

−

−OH
(Salphonic acid)

sulphonic acid

sulpho

(3)

Anhydride

Oic anhydrid (when carbon(C) of this functional group present in the main chain)
or

Carboxylic anhydride (when carbon(C) of this functional group is not present in the main chain)

(4)

esters

Oate (when carbon(C) of this functional group present in the main chain)or
Carboxylate (when carbon(C) of this functional group is not present in the main chain)

(5)

Acid halides

Oyl halide (when carbon(C) of this functional group present in the main chain)or
Carboxyl halide (when carbon(C) of this functional group is not present in the main chain)

haloflormyl

(6)

Amides
R−

−NH2

amide (when carbon(C) of this functional group present in the main chain)
or
carbamide (when carbon(C) of this functional group is not present in the main chain)

carbamoyl

(7)

cynide (−C≡N)

nitrile (when carbon (C) of this functional group present in the main chain)
or
carbonitrile (when carbon(C) of this functional group is not present in the main chain)

cyano

(8)

−N

→

Carbylamine

isocyano

(9)

−

−H

al (when carbon(C) of this functional group present in the main chain)
or
Carbaldehyde (when carbon(C) of this functional group is not present in the main chain)

formyl(oxo)

(10)

−

one

oxo

(11)

−OH

hydroxy

(12)

−SH

thiol

mercapto

(13)

−NH2

amine

amino

From this table you can see −COOH has highest priority and −NH2 has lowest priority among all functional group

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