Question

Which of the following is position and chain isomer of

:

• A. $C{H}_3-\stackrel{O}{\stackrel{||}{C}}-\underset{C{H}_3}{\underset{|}{CH}}-CH3$
• B. $C{H}_3-C{H}_2-C{H}_2-C{H}_2-CHO$
• C. $C{H}_3-\stackrel{O}{\stackrel{||}{C}}-\stackrel{C{H}_3}{\stackrel{|}{CH}}-CH3$
• D. $C{H}_3-C{H}_2-C-C{H}_2-C{H}_3$

Answer 1

Answer: (A), (C)

$C{H}_3-\stackrel{O}{\stackrel{||}{C}}-\stackrel{C{H}_3}{\stackrel{|}{CH}}-CH3$

We know about chain and position isomers.

First check the molecular formula:

$C{H}_3-C{H}_2-\stackrel{O}{\stackrel{||}{C}}-C{H}_2-C{H}_3$

$\to$ $C_5{H}_{10}O$

Option (a) $\to$ $C_5{H}_{10}O$

Option (b) $\to$ $C_5{H}_{10}O$

Option (c) $\to$ $C_5{H}_{10}O$

Option (d) $\to$ $C_5{H}_{10}O$

So,molecular formula of all the structures is same.

To be a position and chain isomer ,it should follow the conditions of both.

$\to$ Option (b) has a different functional group(-CHO). Therefore, it is neither position nor chain isomers.

$\to$ Option (d) is a position isomer but not chain isomer.

If you look at option (a) and (c) closely,they both are same.

$C{H}_3-\stackrel{O}{\stackrel{||}{C}}-\stackrel{C{H}_3}{\stackrel{|}{CH}}-CH3$

$C{H}_3-\stackrel{O}{\stackrel{||}{C}}-\underset{C{H}_3}{\underset{|}{CH}}-CH3$

3-Methybutan-2-one 3-Methylbutan-2-one

It follows conditions for both position and chain isomerism.

Therefore,

Option (a) and (c) both are correct.