Chemistry MCQs for NEET — Practice Questions with Answers

In a homologous series, the compounds share a general formula. For example, alkanes have the general formula $C_nH_{2n+2}$, alkenes have $C_nH_{2n}$, and alcohols have $C_nH_{2n+1}OH$. This general formula helps in predicting the molecular formula of the compounds in the series.

In a homologous series, the physical properties of the compounds, such as boiling and melting points, gradually change with an increase in molecular mass. Thus, they do not have identical physical properties. The similar chemical properties and the ability to be represented by a general formula are true characteristics of a homologous series.

The molecular formula $C_5H_{12}$ corresponds to pentane, which has three chain isomers: n-pentane, isopentane (methylbutane), and neopentane (dimethylpropane).

2-chlorobutane and 3-chlorobutane are positional isomers because they differ in the position of the chlorine atom on the carbon chain. In 2-chlorobutane, the chlorine is attached to the second carbon, while in 3-chlorobutane, it is attached to the third carbon.

The formula $C_4H_{10}O$ can give rise to three ether metamers: 1. Diethyl ether (CH$_3$CH$_2$OCH$_2$CH$_3$), 2. Methyl propyl ether (CH$_3$OCH$_2$CH$_2$CH$_3$), and 3. Ethyl methyl ether (CH$_3$CH$_2$OCH$_3$). These are the three possible structures, hence the correct option is 3.