Chapter 3: Q14P (page 99)

Draw the structure and give the systematic name for a compound with molecular formula C₅H₁₂ that has
a. only primary and secondary hydrogens.
b. only primary hydrogens.
c. one tertiary hydrogen.
d. two secondary hydrogens.

Short Answer

Expert verified

Step by step solution

a) Step 1: Selection of chain

Because pentane is the name of the parent hydrocarbon with the molecular formula the longest continuous chain has 5 carbons. Now, draw and number the parent hydrocarbon.

Determine substituents

Now, arrange the parentcarbon in such a way so that contains only primary and secondary hydrogen.

A primary hydrogen is a hydrogen that is attached to a primary carbon (-CH₃).
A secondary hydrogen is a hydrogen that is attached to a secondary carbon (-CH₂), so the structure becomes as shown below.

Draw the structure

The name of the structure is n-pentane or normal pentane.

b) : Selection of chain

Because pentane is the name of the parent hydrocarbon with the molecular formula C₅H₁₂, the longest continuous chain has 5 carbons. Now, draw and number the parent hydrocarbon.

Determine the substituents

Now, arrange the parent carbon in such a way that contains only primary hydrogens.

A primary hydrogen is a hydrogen that is attached to a primary carbon (-CH₃).

Draw the structure

The name of the structure is 2,2-dimethylpropane.

c) : Selection of chain

Because pentane is the name of the parent hydrocarbon with the molecular formula C₅H₁₂, the longest continuous chain has 5 carbons. Now, draw and number the parent hydrocarbon.

Determine the substituents

Now, arrange the parent carbon in such a way such that it contains one tertiary hydrogen.

A tertiary hydrogen is a hydrogen that is attached to a tertiary carbon (-CH).

Draw the structure

The name of the structure is 2-methylbutane.

d) Selection of chain

Because pentane is the name of the parent hydrocarbon with that molecular formula C₅H₁₂, the longest continuous chain has 5 carbons. Now, draw and number the parent hydrocarbon.