Find out the total number of isomeric molecules form on dichlorination of cyclopentane/

Name: Problem 163, Chapter 23: A Complete Resource Book in Chemistry for JEE Main
Uploaded: 2019-03-11T03:57:32-08:00
Duration: 5 min 27 s
Channel: Chloe Schroeder
Description: Find out the total number of isomeric molecules form on dichlorination of cyclopentane/

Find out the total number of isomeric molecules form on...

Key Concepts

Stereochemistry

Stereochemistry involves the study of the three-dimensional arrangement of atoms within molecules. This concept is important when examining reactions that yield stereoisomers, such as cis/trans isomers, because the spatial orientation of substituents in cyclic compounds can lead to significant differences in the properties and reactivities of the products.

Cycloalkane Structure and Symmetry

Cycloalkanes are ring-shaped molecules that often exhibit a high degree of symmetry. This symmetry means that certain positions on the ring are equivalent, which can reduce or complicate the number of unique isomeric products formed during a substitution reaction. A clear understanding of the symmetry in cyclic compounds is essential when predicting outcomes in reactions like dichlorination.

Isomerism

This concept refers to the phenomenon where molecules with the same molecular formula can exist in different forms by virtue of variations in the connectivity of their atoms (constitutional isomers) or their spatial arrangement (stereoisomers). It is a central topic in organic chemistry, especially when considering reactions that may yield multiple distinct products from a single precursor.

Substitution Reactions

Substitution reactions are processes in which one or more atoms in a molecule are replaced by different atoms or groups. In the context of halogenation reactions, such as dichlorination, hydrogen atoms in hydrocarbons are replaced by chlorine atoms. Understanding substitution reactions is crucial to predicting the formation of various isomers during a halogenation process.

Transcript

00:01 We know that in order for a carbon to be neutral and have a full octet, it must have four bonds.

00:08 So let's start with this carbon.

00:11 It is at the end of a chain.

00:12 It is a carbon.

00:14 It is attached to one oxygen, so it only has one bond, meaning it must have three other bonds to be neutral.

00:20 So this carbon has three hydrogens attached to it.

00:24 Move over to this carbon.

00:26 It currently has one, two, three, four bonds.

00:29 So it can't have any more bonds.

00:32 It has zero hydrogens attached to it.

00:35 This carbon has one, two, three, four bonds, so it also doesn't have any hydrogens attached to it.

00:43 This one has one, two, three bonds.

00:45 It needs one more, therefore there must be one hydrogen coming off of this carbon.

00:51 This carbon has one, two, three bonds.

00:54 It must have one more to have a full octet and to be neutral, so it has one hydrogen.

00:59 This carbon has one, for the same as these two also has one hydrogen.

01:04 This carbon has one, two, three, four bonds.

01:07 It doesn't need any more, therefore there are not any implied hydrogens on that carbon.

01:12 This one has one, two bonds.

01:14 It needs two more, therefore there are two implied hydrogens attached to that carbon.

01:20 This one has one, two, three, four bonds.

01:24 So there are zero hydrogens attached to that carbon every has all four bonds.

01:29 This one has one, two bonds, meaning there are two bonds, more hydrogens same with this carbon this carbon and this carbon each only has two bonds therefore it must have two more implied hydrogens attached to it this carbon has one two three bombs so it needs one more it must be to a hydrogen same with this carbon it currently only has three bonds the last bond is an implied hydrogen this carbon has one two three bonds it all also has a hydrogen coming off of it, the central carbon here.

02:08 This one only has one bond.

02:10 It needs three more, so there must be three implied hydrogens attached to it.

02:15 And same with this methyl group.

02:18 Moving over to our second compound, let's start with this aromatic ring.

02:22 This carbon has one, two, three bonds.

02:24 It needs one more, so it must be bonded to one hydrogen.

02:28 This carbon is bonded to one, two, three carbons.

02:32 It needs one more bond to a hydrogen.

02:35 Same with this carbon, this carbon, this carbon, this one, this one, this one, this one, this one, and this one.

02:46 All have one hydrogen attached to it for the same reason.

02:49 They all have three bonds in need of fourth.

02:52 If we look at these two carbons, they have the same bonding.