Question

Match the following.

	Column I		Column II
A	Acetaldehyde, vinyl alcohol	1	Enantiomers
B	Eclipsed and staggered ethane	2	Tautomers
C	(+)2-butanol, (-)2-butanol	3	Chain isomers
D	Methyl-n-propylamine and diethylamine	4	Conformational isomers
		5	Metamers

• A. $A \to 1, B \to 4, C \to 3, D \to 5$
• B. $A \to 2, B \to 4, C \to 1, D \to 5$
• C. $A \to 5, B \to 1, C \to 4, D \to 2$
• D. $A \to 5, B \to 1, C \to 3, D \to 2$

Answer 1

Answer: (B)

$\underset{\text{acetaldehyde}}{CH _{3} CHO} \xrightarrow{\text { Tautomerisation }}\underset{\text{vinyl alcohol}}{CH _{2}= CH - OH}$
Thus, these two are tautomers.
Eclipsed and staggered ethane are two conformations of ethane.
(+)2-butanol and (-)2-butanol are enantiomers as these are non-superimposable mirror images.

$\underset{\text{(methyl- $n$ -propylamine)}}{CH _{3} NHC _{3} H _{7}}$ and $ \underset{\text{(diethylamine)}}{C _{2} H _{5} NHC _{2} H _{5}}$
Due to difference in the nature of alkyl groups attached to the same functional group, these are called metamers.