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)

$\underset{\text{acetaldehyde}}{C{H}_{3}CHO}\stackrel{\text{ Tautomerisation }}{\to }\underset{\text{vinyl alcohol}}{C{H}_2=CH-OH}$
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.

$\underset{\text{(methyl- n -propylamine)}}{C{H}_{3}NH{C}_3{H}_7}$ and $\underset{\text{(diethylamine)}}{C_2{H}_{5}NH{C}_2{H}_5}$
Due to difference in the nature of alkyl groups attached to the same functional group, these are called metamers.