MCQ Detailed View

In chemistry, the term homologous refers to compounds that belong to a homologous series. A homologous series is a group of organic compounds that have the same general formula, similar chemical properties, and differ from each other by a fixed unit, usually –CH₂–.

Compounds in a homologous series have the same functional group, which is responsible for their similar chemical properties. For example, the alcohol series (methanol, ethanol, propanol, etc.) all contain the –OH functional group. Despite differences in molecular size, all alcohols react in similar ways with oxidizing agents, acids, and other chemicals because their chemical behavior is determined by the functional group.

The differences between members of a homologous series are primarily in their physical properties, such as boiling point, melting point, and solubility, which gradually change with the addition of –CH₂– units. However, their chemical properties remain the same, which is why the correct answer is “Same chemical properties.”

Other options, like “same chemical numbers” or “different chemical properties,” are incorrect. While the molecular formula changes by one –CH₂– unit from one member to the next, it is the functional group that determines chemical behavior, not the total number of atoms.

Understanding the concept of homologous compounds is fundamental in organic chemistry. It helps students classify compounds, predict chemical reactions, and understand the pattern in physical properties across a series. Homologous series provide a clear framework for studying alkanes, alkenes, alkynes, alcohols, carboxylic acids, and other organic compounds, making it a key concept in everyday chemistry studies.