Question

Define isomerism. Give IUPAC the name of an isomer of ${C_4}{H_{10}}$ which has branched chain.

Answer 1

Hint: Isomerism is a term that is related to the existence of two or more compounds differing in their chemical structure. Isomers are the compounds that differ in spatial arrangement of atoms in space. Hydrocarbons are the compounds that contain only carbon and hydrogen.

Complete step by step answer:
Isomerism is a phenomenon in which more than one compound has the same chemical formula but different chemical structures.
Chemical compounds that have identical chemical formulas but have different arrangements of atoms and differ in their properties are called isomers.
There are different types of isomers. Constitutional isomers are one of them.
Constitutional isomers : Isomers that differ in connectivity are called constitutional isomers. They have the same parts but those parts are connected to each other in a different manner.
The given compound is ${C_4}{H_{10}}$ . It is a hydrocarbon. Hydrocarbons are the compounds that contain only hydrogen and carbon. There are different types of hydrocarbon- saturated and unsaturated.
Saturated compounds have a single bond in the molecule. Such compounds belong to the class “alkanes”. Alkanes have a general molecular formula ${C_n}{H_{2n + 2}}$ where $n$ is the number of carbon atoms. The first member of the series is methane $(C{H_4})$ , ethane $({C_2}{H_6})$, propane $({C_3}{H_8})$ . So ${C_4}{H_{10}}$ belongs to the alkane family and is called as butane. Its structure can be shown as-

The simplest hydrocarbons- methane $(C{H_4})$ , ethane $({C_2}{H_6})$ and propane $({C_3}{H_8})$ have no constitutional isomers as there is no way to connect the carbon and hydrogen in a different way but after propane all other homologous members have constitutional isomers.
IUPAC name of isomer ${C_4}{H_{10}}$ which has branched chain is $2 - $ methyl propane. There are also other isomers possible but the isomer which has branched chain is $2 - $ methyl propane.

Note: The given compound was a saturated compound with more than three carbon atoms and hence was capable of showing positional isomerism. Saturated compounds can show all types of isomerism except geometrical isomerism.
Unsaturated compounds show geometrical isomerism because in unsaturated compounds the position of molecules are locked to each other due to the presence of ring structure or double bond.