Chapter 19, Problem 16PE

(a)

Interpretation Introduction

Interpretation:

Structures of 2-dimethylbutane and 2,2-dimethylbutane has to be drawn and incorrect the name has to be indicated.

Concept introduction:

IUPAC Nomenclature:

IUAC gives rules for the naming of chemical compounds. These rules are,

For saturated hydrocarbons, longest chain is the parent chain of the compound and remaining groups and atoms are consider as substituent.

In the nomenclature, Find the parent chin first then number the carbon atoms in the parent chain followed by designate the substituent in its position in parent chain.

If more than one same substituent were occurs, add a prefix (di-, tri-, tetra-, ect..) in front of parent chain name.

Finally the systematic name was written as, the substituent position number with prefix (di-, tri-, tetra-, ect..) of number of substituents followed by name of the substituent then write the parent chain name (which contains large number of carbon atoms in the chain).

The parent chain names based on the carbon atoms are,

$\begin{array}{l}{\text{CH}}_{\text{3}}{\text{-CH}}_{\text{2}}\text{- }\text{Ethane}\\ {\text{CH}}_{\text{3}}{\text{-CH}}_{\text{2}}{\text{-CH}}_{\text{2}}\text{-}\text{Propane}\\ {\text{CH}}_{\text{3}}{\text{-CH}}_{\text{2}}{\text{-CH}}_{\text{2}}{\text{-CH}}_{\text{2}}\text{-}\text{Butane}\\ {\text{CH}}_{\text{3}}{\text{-CH}}_{\text{2}}{\text{-CH}}_{\text{2}}{\text{-CH}}_{\text{2}}\text{-}{\text{CH}}_{\text{2}}\text{-}\text{Pentane}\end{array}$

The substituent names based on the carbon atoms are,

$\begin{array}{l}{\text{CH}}_{\text{3}}\text{-}\text{methyl}\\ {\text{CH}}_{\text{3}}{\text{-CH}}_{\text{2}}\text{- }\text{ethyl}\\ {\text{CH}}_{\text{3}}{\text{-CH}}_{\text{2}}{\text{-CH}}_{\text{2}}\text{-}\text{propyl}\end{array}$

(b)

Interpretation Introduction

Interpretation:

Structures of 2,4-dimethylhexane and 2-ethyl-4-methyl-pentane have to be drawn and incorrect the name has to be indicated.

Concept introduction:

Refer part (a).