Question

Write the chemical formula of 2-chloro-2-methylpropane.

Answer 1

The general formula of saturated hydrocarbons (alkanes) is ${{\text{C}}_n}{{\text{H}}_{2n + 2}}$.
The general formula of mono-chloro derivatives obtained from saturated hydrocarbons (alkyl chlorides) is ${{\text{C}}_n}{{\text{H}}_{2n + 1}}{\text{Cl}}$ .

Complete step by step answer:
Halogen derivatives of alkanes are obtained when one (or more) hydrogen atoms of alkanes are replaced with halogen atoms. Halogens means fluorine, chlorine, bromine and iodine. In halogen derivatives of alkanes one or more halogen atoms may be present. Also, only one type of halogen may be present or two or more types of halogens may be present. Thus, it may happen that one chlorine atom and one bromine atom is present. When two halogen atoms are present in the same carbon atom, then you can call it as geminal dihalide. When two halogen atoms are present on adjacent carbon atoms, then you can call it vicinal halide. When only one halogen atom is present, you call it monohalogen derivative. If several halogen atoms are present, you call it a polyhalogen derivative.
The parent hydrocarbon in 2-chloro-2-methylpropane is propane. Propane has 3 carbon atoms and 8 hydrogen atoms. These three carbon atoms form a chain. Write the structural formula of propane.
${\text{C}}{{\text{H}}_3}{\text{C}}{{\text{H}}_2}{\text{C}}{{\text{H}}_3}$ or ${{\text{C}}_3}{{\text{H}}_8}$
Replace the hydrogen atom and add a methyl substituent on the second carbon atom and write the formula.
${\text{C}}{{\text{H}}_3}{\text{CH}}\left( {{\text{C}}{{\text{H}}_3}} \right){\text{C}}{{\text{H}}_3}$ or ${{\text{C}}_4}{{\text{H}}_{10}}$
Replace the hydrogen atom and add a chlorine substituent on the second carbon atom and write the formula.
${\text{C}}{{\text{H}}_3}{\text{CCl}}\left( {{\text{C}}{{\text{H}}_3}} \right){\text{C}}{{\text{H}}_3}$ or ${{\text{C}}_4}{{\text{H}}_9}{\text{Cl}}$

Thus, the chemical formula of 2-chloro-2-methylpropane is ${{\text{C}}_4}{{\text{H}}_9}{\text{Cl}}$.

Note: 2-chloro-2-methylpropane is mono-chloro derivative (alkyl chloride) obtained from 2-methylpropane. The chemical formula of 2-chloro-2-methylpropane is ${{\text{C}}_n}{{\text{H}}_{2n + 1}}{\text{Cl = }}{{\text{C}}_4}{{\text{H}}_{2(4) + 1}}{\text{Cl}} = {{\text{C}}_4}{{\text{H}}_9}{\text{Cl}}$ .