NCERT Class 11 Chemistry Chapter 12 Notes Organic Chemistry- Some Basic Principles and Techniques

Organic chemistry is the branch of chemistry that studies the compounds containing carbon. We often used to hear that, this thing is organic, So what does organic mean? Basically organic compounds are those compounds which are made up of living organisms or occur naturally but apart from that organic compounds can be prepared in labs as well. We use a lot of things in our day-to-day lives like soaps, shampoo, medicines, perfumes, food, plastic, etc. Have you ever wondered what they are made of? So, the answer to this question is organic compounds, most of these things are made of organic compounds.

This Story also Contains

1. NCERT Class 11 Chapter 12 Notes
2. Functional groups
3. Homologous series
4. Nomenclature
5. Isomerism
6. Reaction Mechanism Included in Fundamental Concepts of Chemistry
7. Estimating Carbon and Hydrogen
8. NCERT Class 11 Notes Chapter-Wise
9. Subject Wise NCERT Exemplar Solutions
10. Subject Wise NCERT Solutions

NCERT Class 11 Chemistry Chapter 8 notes are prepared by our subject experts, ensuring the relevance and credibility of the content provided inside. based on finding the. The chapter Organic Chemistry: Some Basic Principles and Techniques Class 11 notes include topics like the reason for tetravalence and writing the names of an organic structure with rules, the IUPAC nomenclature and the concept of mechanism for organic reactions. If students are facing difficulty in understanding the concepts provided inside the NCERT textbook, then they can refer to NCERT Chemistry notes.

CBSE class 11 chemistry some basic principles and techniques notes included the topics stepwise in which firstly students get an idea about the nomenclature and structures of different compounds after that mechanism of different reactions and their specific results. Further, the chapter gives a brief about different effects such as resonance, isomeric, etc as well as the methods for estimating the nitrogen in CBSE class 11 chemistry chapter 8 notes.

Also, students can refer,

NCERT Class 11 Chapter 12 Notes

Topics to be covered according to NCERT textbooks are given below:

Organic compounds: This can be defined as the branch of chemistry which includes the study of hydrocarbons and their derivatives

Shapes related to carbon compounds

It is seen that three types of hybridization basically involve organic compounds with s and p orbitals. In this alkanes have a tetrahedral shape with sp³ hybridization, alkenes have a planar shape with sp² hybridization and alkynes have a linear shape with sp hybridization.

Functional groups

There are numerous functional groups available to make compounds, they are groups of atoms when joined specifically to carbon. We can easily determine the chemical behaviour because all of them contain different chemical properties.

Homologous series

The series can be defined as those compounds that have same chemical properties, same functional group attached but only can be differentiated using formula unit-CH₂.

General formula of such series of compounds are similar.

Nomenclature

Naming of organic compounds on the basis of common name system:

The common naming system indicates that initially we gave the names to compound on the basis of their origin. For example: urea is found in animal’s urine so the common name is urea. Another example of common naming system is formic acid as this can be obtained from red ants whose scientific name is Formica.

IUPAC nomenclature:

The IUPAC denotes International Union of Pure and Applied Chemistry. For giving the names as according to IUPAC nomenclature system they follow the three rules.

1. Suffix

2. Prefix

3. Word root

Suffix may be of two types: primary and secondary. In primary suffix single bond is named as ane, double bond is named as ene and triple bond named as yne. Whereas in case of secondary suffix it will depends on the functional group to which they are attached.

Prefix are also two types: primary and secondary and these are part of word root. In primary prefix we take an example of cyclopropane where cyclo is used first as prefix, but in case of secondary prefix, substituted groups are attached.

Example:

Substituted group Secondary prefix

-F Fluoro

-Cl Chloro

-Br Bromo

-NO Nitroso

Compounds that contains functional groups:

The compounds that contain functional groups in it are numbered in such a way that lowest carbon attached to functional group contains lowest in number.

In case many functional groups are attached to the chain than principal functional group is selected to name the compound and that principal functional group is according to preference.

Isomerism

The compounds having the same molecular formula but differ in structure are termed as isomers and the phenomenon are termed as isomerism.

Reaction Mechanism Included in Fundamental Concepts of Chemistry

Reaction mechanism depends on the fission of covalent bonds in two ways:

• Homolytic Fission

• Heterolytic Fission

Electrophile:

Electrophiles are those species that are charged positively or are neutral in nature.

The species are basically electron deficient. For example: H₂O⁺,CH₃,SO₃,CHCl₂,NH₄⁺, etc.

Nucleophile:

Nucleophiles are the species that are charged negatively or are neutral in nature.

The species contains lone pair of electron. For example: H₂O:R₃N, cyanide.

Displacements of electron can be possible inside covalent bond let us see some of the effects related to it.

Electron displacement occur in an compound which is bonded covalent, because of atom or groups of atom, or by electronegativity, or attached groups.

The effects are as follows:

• Inductive effect

• Elecromeric effect

• Resonance effect

• Hyperconjugation effect

Inductive effect:

Involvement of carbon electron as the two atoms are shared between the atom equally.

Due to difference in their electronegativity than electron will displaces more towards the more electronegative atom which cause polarity. This results in more electronegative atom attain small negative charge on the other hand less will attain small positive charge.

Common atoms or group of atoms shows some of the effects such as the +I effect and -I effect.

- I effect: These are atoms or compounds which are electrons attractive in nature.

+ I effect: These are atoms or compounds which are electrons released in nature.

Resonance effect:

Some of the organic compounds are not represented by a single structure so we need a structure that is stable in nature.

Resonance is defined as where we can make two or more structures for the same compound and the atoms in that are also identified such structure is termed as Resonance structure.

• The hybridisation of all the carbon atoms in benzene rings is found to have sp² hybridisations. The overlapping of hybrid orbitals are done in such a way that all s orbitals of a hydrogen atom from sigma bond with carbon and also carbon-carbon bonds.

• With the help of X-ray diffractions, benzene is found as planar in structure.

• The bond length of carbon-carbon (139) which is intermediated between C-C of bond length(133pm) and C-C of bond length (154) is of the same bond order. So, under normal benzene will go for addition reactions, which is the unusual behaviour of benzene.

• Below is the resonance structure of benzene.

Resonance effects are of two types:

• Positive resonance or mesomeric effect

• Negative resonance or mesomeric effect

Positive resonance effect: Loss of electron towards the carbon atom are +R effect.

Negative resonance effect: Electron which are drawn away from carbon are termed as -R effect.

Electromeric effect:

The electromeric effect is the effect that shows the polarity among the atom bonded by multiple bonds, when the multiple bonds like double or triple bonds are attacked by electrophile the two pi electrons transfer to one of the atoms. The attack can be possible in the presence of reagents.

Positive electromeric effect: (+E) The positive effect can be shown by pi electrons attached to that site of the atom where reagents attacked.

Negative electromeric effect: (-E) The positive effect can be shown by pi electrons attached to that site of the atom where reagents do not attack.

Hyperconjugation effect:

The inductive effect gets reversed when the alkyl group is attached to the unsaturated system.

Organic chemistry: Some basic principles and techniques Class 11th Notes- Topic 4:

Qualitative analysis

• Copper oxide test:

This can be done for the detection of carbon and hydrogen.

• Lassaigne’s test:

For detection of nitrogen, sulphur, halogen and phosphorous when present in an organic compound.

• Nitrogen test:

• Sodium test:

• Halogen test:

• Phosphorous test:

Estimating Carbon and Hydrogen

• The carbon and hydrogen can be determined by taking the organic compound and burning them in excess of oxygen and copper(II) oxide.

• The oxygen oxidised the carbon and hydrogen to form carbon dioxide and water.

• The amount of carbon ad hydrogen is calculated, to know the exact percentage.

CxHy+y/2O₂^→xCO₂+yH₂O

Let, the organic compound contains mass=mg

Water containing the mass=m1g

Carbon dioxide containing the mass=m2g

% of carbon present=12×m2×10044×m

% of hydrogen present=12×m1×10044×m

Estimation for nitrogen:

In this basically, we use two methods:

• Dumas Method

• Kjedahl’s Method

Dumas Method:

The method is used in the estimation of nitrogen, which when heated with copper oxide produces free nitrogen in the presence of carbon dioxide.

Kjedahl’s Method:

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