Railways Chemistry Organic Chemistry: Some Basic Principles & Techniques / कार्बनिक रसायन : कुछ मूलभूत सिद्धांत एवं तकन General Organic Chemistry

General Organic Chemistry

• Wohler prepared the first organic compound urea while preparing ammonium cyanate.
• Classification of organic compounds:

The existence of two or more chemical compounds with the same molecular formula but having different properties owing to different arrangement of atoms within the molecule is termed as isomerism

• Hydrocarbons: All those compounds which contain just carbon and hydrogen are called hydrocarbons.
• Functional group: The atom or group of atoms which determine the properties of a compound is known as functional group. e.g. \[-OH\] (alcohol), -CHO (aldehyde), > C = C < (alkene), \[-C\equiv C-\] (alkyne), etc.
• Homologous Series: A series of compounds in which the same functional group substitute’s hydrogen in a carbon chain is called a homologous series, e.g. \[C{{H}_{3}}Cl\] .and \[{{C}_{2}}{{H}_{5}}Cl\] differ by a \[-C{{H}_{2}}\] unit.
• Nomenclature: Chemists developed a set of rules, for naming organic compounds based on their structures which is known as IUPAC rules. The IUPAC name of an organic compounds consists of three parts.

Prefix - word root - Suffix

Word root: A word root indicates the nature of basic carbon skeleton.

• In case a functional group is present, it is indicated in the name of the compound with either as a prefix or as suffix.
• While adding the suffix to the word root the terminal 'e' of carbon chain is removed
• If the carbon chain is unsaturated then the final 'ane' in the name of the carbon chain is substituted by 'ene' or ‘yne’ respectively for double and triple bonds.

• Chemical Properties of Carbon Compounds

(i) Combustion: Carbon compound undergo combustion reaction to produce \[C{{O}_{2}}\] and \[{{H}_{2}}O\] with the evolution of heat and light \[C{{H}_{4}}+{{O}_{2}}\to C{{O}_{2}}+{{H}_{2}}O+\]heat and light

(ii) Oxidation: \[\underset{ethanol}{\mathop{C{{H}_{3}}C{{H}_{2}}OH}}\,\xrightarrow{alk.\,\,KMn{{O}_{4}}/\Delta }\underset{ethanoic\,\,acid}{\mathop{C{{H}_{3}}COOH}}\,\]

The substance which are used for oxidation are known as oxidising agent, e.g alkaline\[KMn{{O}_{4}}\], acidified\[{{K}_{2}}C{{r}_{2}}{{O}_{7}}\].

(iii) Addition reaction:

Unsaturated hydrocarbons (alkenes and alkynes undergo addition reaction in presence of catalysts e.g.

(iv) Substitution reaction: Saturated hydrocarbons give substitution reaction e.g. methane in presence of sunlight undergo chlorination.