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Revision: Class 11 >> Some Basic Principles of Organic Chemistry NEET (UG) Some Basic Principles of Organic Chemistry

Definitions [8]

Definition: Inorganic Chemistry

The branch of chemistry that deals with compounds obtained from non-living sources or minerals, such as common salt, blue vitriol, and nitrates.

Definition: Organic Chemistry

The branch of chemistry that deals with compounds originally derived from living organisms, such as sugar, starch, proteins, and acetic acid.

Define Homologous series.

A series of compounds with similar chemical properties, in which members differ from one another by an additional CH₂ group, is called a homologous series.

Definition: Homologous Series

The same functional group substitutes for hydrogen in a carbon chain is called a homologous series.

A homologous series is a group of organic compounds having similar structure and similar chemical properties in which the successive compounds differ by a CH₂ group.

The series of compounds formed by joining the same functional group in the place of a particular hydrogen atom on the chains having sequentially increasing length is called homologous series.

Definition: Isomers

Compounds having the same molecular formula but different structural formula are known as Isomers and the phenomenon is known as Isomerism. (iso = same, meros = parts).

Define sublimation.

The change of state from solid to gas directly is called sublimation.

Definition: Sublimation

The change of a solid substance directly into a gas or vapour without first changing into a liquid is called sublimation.

The change from solid state to vapour state without passing through the liquid state is called sublimation, and the substance is said to sublime.

Define the Stationary phase.

Stationary phase is a solid or a liquid supported on a solid which remains fixed in a place and on which different solutes are adsorbed to a different extent.

Key Points

Key Points: Rules of Nomenclature

Longest Chain: Choose the longest continuous carbon chain as the parent chain.
Numbering: Number the chain so that branches or functional groups get the lowest possible numbers.
Substituents: Name and position of alkyl groups are placed before the parent name (e.g., 3-methylpentane).
Multiple Groups: Use prefixes like di-, tri-, etc., for repeated groups (e.g., 2,2-dimethylbutane).
Alphabetical Order: Different substituents are listed alphabetically (e.g., 2-bromo-4-chlorohexane).

Key Points: Homologous Series

A homologous series is a group of compounds with the same functional group and similar chemical properties.
Successive members differ by one CH₂ (methylene) unit, increasing the molecular mass by 14 u.
All members of a homologous series follow the same general molecular formula (e.g., alkanes C_nH_2n+2).
Physical properties such as boiling and melting points show a gradual change with increasing molecular mass.
Knowing the properties of a few members helps predict the properties of other members in the series.