Chapter 19, Problem 86AE

(a)

Interpretation Introduction

Interpretation:

The given alcohol name is $\text{ethyl}\text{alcohol}$ has to be converted into its structure by the reverse naming process.

Concept Introduction:

Alcohols:

Alcohols are organic compounds whose molecules contains the hydroxyl $\left(-\text{OH}\right)$ functional group bonded to ${\text{sp}}^3$ hybridized carbon. The general formula of alkyl halides is represented as follows:

Common Name Rules:

• Identify and name the alkyl group bonded to the ${\text{sp}}^{\text{3}}$ hybridized oxygen atom.
• Add the word alcohol at the end of the alkyl group’s name to get the complete alcohol common name.

Explanation of Solution

The given common name for the alcohol compound is $\text{ethyl}\text{alcohol}$ which contains two parts.

The first part of the alcohol name is $\text{ethyl}$ which contains two carbon atoms. So, draw the two carbon atoms in a straight-line as shown down.

The second part of the common name is alcohol which indicates the hydroxyl functional group in the compound. So, the hydroxyl functional group is attached directly to one of the carbon atoms as shown below.

Now, add the hydrogen atoms to each carbon atom in order to complete the structure because each carbon has four bonds around it.

Hence, the structural formula for $\text{ethyl}\text{alcohol}$ is as follows:

(b)

Interpretation Introduction

Interpretation:

The given alkyl halide name is $\text{iodomethane}$ has to be converted into its structure by the reverse naming process.

Concept Introduction:

Alkyl halides:

Alkyl halides are halogenated hydrocarbons with the formula, $\text{RX}$ in that molecules one of the hydrogen atom is substituted with the halogen atom such as $\text{F}$, $\text{Cl}$, $\text{Br}$ and $\text{I}$. The general formula of alkyl halides is represented as follows:

IUPAC rules for naming alkyl halides:

• Identify the parent carbon chain in the given compound. The halogens and alkyl groups bonded to the parent chain are treated as substituents or branched chains. If two chains have the same carbon lengths, choose the chain with a greater number of substituents bonded to it. Name the parent compound based on the number of carbon atoms present in it.
• The parent carbon chain is numbered from the end of the chains whose alkyl groups must have the lowest possible locants.
• Identify and name the alkyl groups including their positions on the parent carbon chain.
• If the parent carbon chain contains two or more same kinds of alkyl groups, indicate this repetition by a numerical multiplier ($di\text{-}$, $tri\text{-}$ and so on) used before the alkyl-group name. The numbers for alkyl group positions are separated by a comma and the alkyl-group name and the position number is separated by a hyphen.
• If the parent carbon chain contains several different alkyl groups, arrange them in alphabetical order (do not consider numerical multipliers). Write all alkyl group names that include their locants in front of the parent compound’s name.

Explanation of Solution

The given IUPAC name for the alkyl halide is $\text{iodomethane}$. In alkyl halides, the hydrogen atom in the ${\text{sp}}^{\text{3}}$ hybridized carbon is substituted with a halogen atom. Hence, the structural formula for $\text{iodomethane}$ is as follows:

(c)

Interpretation Introduction

Interpretation:

The given alkyl halide name is $\text{2-chloropentane}$ has to be converted into its structure by the reverse naming process.

Concept Introduction:

Refer to part (a).

Explanation of Solution

The given IUPAC name for the alkyl halide is $\text{2-chloropentane}$ so that the parent compound’s name is pentane which contains five carbons. So, draw the five carbon atoms in a straight-line as the parent carbon chain as shown below.

The substituent in the compound is chlorine which is bonded to $\text{C-2}$ in the parent carbon chain. So, draw the chlorine substituet on the parent carbon chain as follows.

Now add the hydrogen atoms to each carbon atom in order to complete the structure because each carbon has four bonds around it.

Hence, the structural formula for $\text{2-chloropentane}$ is as follows:

(d)

Interpretation Introduction

Interpretation:

The given alcohol name is $tert\text{-butyl}\text{alcohol}$ has to be converted into its structure by the reverse naming process.

Concept Introduction:

Refer to part (b).

Explanation of Solution

The given common name for the alcohol compound is $tert\text{-butyl}\text{alcohol}$ which contains two parts.

The first part of the alcohol name is $tert\text{-butyl}$ which contains four carbon atoms. So, draw the structure of $tert\text{-butyl}$ as shown down.

The second part of the common name is alcohol which indicates the hydroxyl functional group in the compound. So, the hydroxyl functional group is attached directly to tertiary carbon atom in the above structure as shown below.

Hence, the structural formula for $tert\text{-butyl}\text{alcohol}$ is as follows: