Question

Compound (s) that on hydrogenation products optically inactive compounds (s) is (are):
(A)
(B)
(C)
(D)

Answer 1

. To solve this question we should know what hydrogenation is and when a compound is said to be optically active or optically inactive. It is very important to be aware of hydrogenation of alkene.

Complete step by step answer: The process of addition of hydrogen molecule to any compound is known as hydrogenation. On hydrogenation of alkene the double is reduced and alkane is produced as the product.
A compound is said to be optically active, when a compound has a chiral carbon because the compounds with chiral carbon can rotate the plane polarised light. The optically inactive compounds are the compounds which do not have a chiral carbon in the first place, hence cannot rotate the plane polarised light.

Option A is .

On hydrogenation, ${H_2}$ reduces the double bond to single bond:

Drawing the product in Fischer projection:

Since the compound has a chiral carbon this compound is optically active. Therefore, Option A is the wrong answer.
Option B is .

On hydrogenation, ${H_2}$ reduces the double bond to single bond:

Drawing the product in Fischer projection:

Since the compound has no chiral carbon this compound is optically inactive. Therefore, Option B is the correct answer.

Option C is .

On hydrogenation, ${H_2}$ reduces the double bond to single bond:

Drawing the product in Fischer projection:

Since the compound has a chiral carbon this compound is optically active. Therefore, Option a c is the wrong answer.
Option D is.

Drawing the product in Fischer projection:

So, the correct answer is “Option B and D”.

Note: When four different groups are attached to a carbon atom, then the carbon atom is said to be chiral carbon. A compound can be optically active only when it has a chiral carbon. Always remember alkanes are formed on hydrogenation of alkenes. Drawing the product in Fischer projection will give better clarity on compounds.