Skip to main content
Ch.3 - Structure and Stereochemistry of Alkanes
Wade - Organic Chemistry 9th Edition
Wade9th EditionOrganic ChemistryISBN: 9780135213728Not the one you use?Change textbook
All textbooksWade 9th EditionCh.3 - Structure and Stereochemistry of AlkanesProblem 5a,b,c
Chapter 3, Problem 5a,b,c

All of the following names are incorrect or incomplete. In each case, draw the structure (or a possible structure) and name it correctly.
a. 3-ethyl-4-methylpentane
b. 2-ethyl-3-methylpentane
c. 3-dimethylhexane

Verified step by step guidance
1
Step 1: Understand the IUPAC naming conventions for alkanes. The longest continuous chain of carbon atoms determines the base name, and substituents are named and numbered according to their position on this chain.
Step 2: For part (a), '3-ethyl-4-methylpentane' suggests a pentane chain with ethyl and methyl groups. However, the longest chain should be identified first. Draw a structure with a five-carbon chain and place the ethyl group on the third carbon and the methyl group on the fourth carbon. Check if a longer chain can be formed by including the substituents.
Step 3: For part (b), '2-ethyl-3-methylpentane' implies a pentane chain with ethyl and methyl groups. Draw a structure with a five-carbon chain, placing the ethyl group on the second carbon and the methyl group on the third carbon. Verify if a longer chain can be formed by including the substituents.
Step 4: For part (c), '3-dimethylhexane' suggests a hexane chain with two methyl groups on the third carbon. Draw a structure with a six-carbon chain and place two methyl groups on the third carbon. Ensure that the longest chain is correctly identified and numbered.
Step 5: After drawing each structure, re-evaluate the longest chain and the positions of the substituents. Rename each compound according to the correct IUPAC rules, ensuring the longest chain is used and substituents are numbered with the lowest possible numbers.

Verified video answer for a similar problem:

This video solution was recommended by our tutors as helpful for the problem above.
Video duration:
9m
Was this helpful?

Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

IUPAC Nomenclature

IUPAC nomenclature is a standardized system for naming chemical compounds. It involves identifying the longest carbon chain as the parent structure, numbering the chain to give substituents the lowest possible numbers, and naming substituents as prefixes. Understanding this system is crucial for correctly naming organic compounds.
Recommended video:
Guided course
03:43
The different parts of an IUPAC name

Alkane Structure

Alkanes are saturated hydrocarbons consisting of carbon and hydrogen atoms with single bonds. The structure of alkanes is determined by the arrangement of carbon atoms in a chain or ring, and the presence of substituents. Recognizing the structure helps in identifying the parent chain and any branches for accurate naming.
Recommended video:
Guided course
02:47
Functionalizing Alkanes

Substituent Positioning

Substituent positioning refers to the location of groups attached to the main carbon chain in a molecule. Correctly identifying and numbering these positions is essential for proper nomenclature. The goal is to assign the lowest possible numbers to substituents, ensuring clarity and consistency in naming.
Recommended video:
4:06
Reactions at the Allylic Position Example 3
Related Practice
Textbook Question

Draw the structures of the following groups, and give their more common names.

a. the (1-methylethyl) group

b. the (2-methylpropyl) group

c. the (1-methylpropyl) group

d. the (1,1-dimethylethyl) group

e. the (3-methylbutyl) group, sometimes called the 'isoamyl' group

1
views
Textbook Question

Write structures for the following compounds.

a. 3-ethyl-4-methylhexane

b. 3-ethyl-5-isobutyl-3-methylnonane

c. 4-tert-butyl-2-methylheptane

d. 5-isopropyl-3,3,4-trimethyloctane

1
views
Textbook Question

Provide IUPAC names for the following compounds.

(d)

(e)

(f)

2
views
Textbook Question

Provide IUPAC names for the following compounds.

a. (CH3)2CHCH2CH3

b. CH3—C(CH3)2—CH3

c.

1
views
Textbook Question

All of the following names are incorrect or incomplete. In each case, draw the structure (or a possible structure) and name it correctly.

d. 4-isobutylheptane

e. 2-bromo-3-ethylbutane

f. 2,3-diethyl-5-isopropylheptane

1
views
Textbook Question

Give structures and names for

a. the five isomers of C6H14

2
views