Question

$1^{\circ },2^{\circ },3^{\circ }and{4}^{\circ }$ carbon atoms are present in?

• A. 2, 2, 4 - Trimethylpentane
• B. 2, 2, 3 - Trimethylpentane
• C. both (a) and (b)
• D. Neither (a) nor (b)

Answer 1

The correct option is B

2, 2, 3 - Trimethylpentane

Let's draw the structure of the following compounds.

2,3,4-Trimethylpentane

$H-\stackrel{H}{\stackrel{|}{\underset{H}{\underset{|5}{C}}}}-\stackrel{H}{\stackrel{|}{\underset{C{H}_3}{\underset{|4}{C}}}}-\stackrel{H}{\stackrel{|}{\underset{C{H}_3}{\underset{|3}{C}}}}-\stackrel{H}{\stackrel{|}{\underset{C{H}_3}{\underset{|2}{C}}}}-\stackrel{C{H}_3}{\stackrel{|}{\underset{H}{\underset{|1}{C}}}}-H$

Now, what do you mean by $1^{\circ },2^{\circ },3^{\circ }and{4}^{\circ }$ carbons?

$1^{\circ }\to$ attached with only one carbon

$2^{\circ }\to$ attached with two carbons

$3^{\circ }\to$ attached with three carbons

$4^{\circ }\to$ attached with four carbons

Now, let us see the compound again.

$H-\stackrel{H}{\stackrel{|}{\underset{H}{\underset{|5}{C}}}}-\stackrel{H}{\stackrel{|}{\underset{C{H}_3}{\underset{|4}{C}}}}-\stackrel{H}{\stackrel{|}{\underset{C{H}_3}{\underset{|3}{C}}}}-\stackrel{H}{\stackrel{|}{\underset{C{H}_3}{\underset{|2}{C}}}}-\stackrel{H}{\stackrel{|}{\underset{H}{\underset{|1}{C}}}}-H$

$c_1\to 1^{\circ }{c}_2\to 3^{\circ }{c}_3\to 3^{\circ }{c}_4\to 3^{\circ }{c}_5\to 1^{\circ }$

2,2,3-Trimethylpentane



We can see that it contains all types of carbons. Hence this is the answer.