Question

1. Identify each pair of compounds as constitutional isomers, stereoisomers, identical molecules, or other.

(a) stereoisomers constitutional isomers other identical molecules (b)identical molecules other stereoisomers constitutional isomers (c) constitutional isomers identical molecules stereoisomers other (d)other identical molecules constitutional isomers stereoisomers

Answer 1

Concepts and reason

Structural relationship between the molecules can be identified based on the arrangement of atoms in the given molecules. This relationship can be of different types namely constitutional isomers and stereoisomers. Pairs of compounds are given; relationship between each pair can be identified using the spatial arrangements of atom.

Fundamentals

Isomers are pairs of compounds, which have same empirical formula but differ in their atomic arrangement or its spatial orientation.

1. Constitutional isomers differ in connectivity of atoms in the molecule.

2. Stereoisomers differ in the spatial orientation of atoms in the molecule.

Stereoisomers are of two types namely enantiomers and diastereomers. Enantiomers are pair of compounds, which are non-superimposable mirror images of each other. Diastereomers are the pair of compounds, which does not have mirror image.

3. Identical molecules are the pair of molecules, which does not have any special relationship with each other.

Block diagram of the above explanation is given below:

Part 1.a

Structural formulas of two compounds are

Relationship between two chemical formulae:

${{\rm{C}}_{\rm{7}}}{{\rm{H}}_{{\rm{14}}}}\,\,{\rm{and}}\,\,\,{{\rm{C}}_{\rm{8}}}{{\rm{H}}_{{\rm{16}}}}$ : Not isomers

Part 1.b

Structural formulas of two compounds are

The relationship between two chemical formulae:

${{\rm{C}}_8}{{\rm{H}}_{{\rm{16}}}}\,\,{\rm{and}}\,\,\,{{\rm{C}}_{\rm{8}}}{{\rm{H}}_{{\rm{16}}}}$ : Isomers

The position of substituents in the given pairs of compounds is given below:

The relationship between the pairs using the position of substituents is:

1, 3-substitution and 1, 4-substitution: Constitutional isomers

Part 1.c

Draw the chemical structures given of each compound in part c

The relationship between two chemical formulae:

${{\rm{C}}_6}{{\rm{H}}_{{\rm{12}}}}\,\,{\rm{and}}\,\,\,{{\rm{C}}_6}{{\rm{H}}_{{\rm{12}}}}$ : Isomers

The position of substituents in the given pairs of compounds is given below:

The relationship between the pairs using theposition of substituents is:

1, 2-substitution and 1, 2-substitution: Stereoisomers

The spatial arrangements of atoms are:

Part 1.d

Chemical structures the given compounds.

The relationship between two chemical formulae:

${{\rm{C}}_{\rm{5}}}{{\rm{H}}_{\rm{8}}}{\rm{C}}{{\rm{l}}_{\rm{2}}}\,\,{\rm{and}}\,\,\,{{\rm{C}}_{\rm{5}}}{{\rm{H}}_{\rm{8}}}{\rm{C}}{{\rm{l}}_{\rm{2}}}$ : Isomers

The positions of thesubstituent in the compounds are:

The relation between the pairs of compounds using positions of the substituents is:

1,3-substitution and 1,3-substitution : Stereoisomers

The spatial arrangement of atoms is:

Ans: Part 1.a

Part 1.b

Part 1.c

Part 1.d

Answer 2

Before we answer this question we need to understand the meaning of each type of isomer option given

01. Stereoisomer

Two compounds only have one difference their spatial arrangements

02.constitutional isomer

Also known as structural isomer have difference in their structure itself

03. Identical molecules

They are not isomer but the one and the same molecules

A) this two moelcules don't have same molecular formula and hence are not any type of isomer so the answer is

other

B) as we can see both the molecules have same molecular formula but one is meta structure and other one is para structure

Which makes it constitutional isomer

So the answer is

constitutional isomer

c) now last has same molecular as well as structural formula only difference is in the spatial arrangements

So the answer is

stereoisomer

I hope this helps. If you have any query or want more detailed explanation, feel free to ask in the comments section below.