Question

$C_6{H}_{14}$ has 2 tertiary carbon atoms. What would be its IUPAC name?

• A. 3-Methylpentane
• B. 3-Methylpentane
• C. Isopentane
• D. 2, 3-Dimethylbutane

Answer 1

The correct option is D

2, 3-Dimethylbutane

A primary carbon atom is attached to only one other carbon atom.

For instance,

$C{H}_3-C{H}_3$ (Both carbons are primary)

$C{H}_3-\underset{C{H}_3}{\underset{|}{C}H}-C{H}_3$ (Except the central carbon atom, the others are primary)

Since the central carbon is attached to 3 other carbon atoms, it is called tertiary.

A secondary carbon would be attached to 2 carbon atoms.

For example, the central carbon in

$C{H}_3-C{H}_{2}C{H}_3$

Similary, the central carbon in

$C{H}_3-\stackrel{C{H}_3}{\stackrel{|}{\underset{C{H}_3}{\underset{|}{C}}}}-C{H}_3$ is quaternary

$C_6{H}_{14}$ is saturated alkane of the form $Cn{H}_{2n+1}$ and it has 2 tertiary carbon atoms.

$\Rightarrow$ The structural formula could only be

$\stackrel{1}{C{H}_3}-\underset{C{H}_3}{\underset{|}{\stackrel{2}{C}}H}-\underset{C{H}_3}{\underset{|}{\stackrel{3}{C}}H}-\stackrel{4}{C{H}_3}$

Wood root = but

primary suffix = ane

Secondary prefix = 2,3-Dimethyl

(d) 2,3-Dimethylbutane