Chapter 23, Problem 15PS

Interpretation Introduction

Interpretation: The structure of two ethylheptane has to be drawn and their systematic name has to be given. The chiral structure among them has to be identified.

Concept introduction:

IUPAC naming for Alkane:

Name the main chain: Find the longest carbon chain and name the chain according to the number of carbon atoms it contains; is also the suffix part of the name.

Number the carbon atoms in the main chain: The carbons are numbered, in which the substituents must get lowest possible numbers.

Identify the substituents, and number each: The number at where substituents are present has to be noted. The substituents written as prefix.

Write the names as a single word: Use the hyphen to separate the numbers from the different prefix; commas to separate numbers. If two or more different substituents are present, arrange them in alphabetical order. If two or more identical substituents are present, use prefixes di-, tri-, tetra-, but this particular prefix should not be used for alphabetizing purpose.

Isomers: Isomers are the compounds which have same molecular formula but have different properties. There are different types of isomers known for example, structural isomers, stereoisomers, geometrical isomers and optical isomers etc

Stereoisomerism: The compounds which have same molecular formula but there is difference in the spatial arrangements of atoms are known as stereoisomers and this phenomenon is known as stereoisomerism.

A chiral carbon is the carbon atom which is substituted to four different groups. Due to presence of chiral carbon a molecule become chiral and it gives optical isomers also that is $R\text{ and }S$ isomers. For example,

  

All the substituents are different hence is is a chiral carbon and so molecule.