Important notes of Compounds Containing Halogens for CBSE & JEE

Compounds Containing Halogens is one of those topics which can fetch you lot of marks very easily. So, go through these important notes of Compounds Containing Halogens to score your best.

 

Organic Compounds Containing Halogens can be divided into two groups:

Alkyl Halides: Aliphatic carbon chain with halogen atom(s) as substitution.. Example: Chlorobutane.

Aryl Halides: Aromatic carbon ring with halogen atom(s) as substitution on ring. Example: Chlorobenzene.

ALSO READ :- 

Important notes of Hydrocarbons for CBSE & JEE

Methods of Preparation of Alkyl Halides:

(a)Grove’s process: Replacement of “OH” group in primary and secondary alcohols with an “X’ atom in presence of Zinc chloride.

The reaction follows SN2 mechanism when the concentration of zinc chloride is low.

(b) Darzen Process: Reaction of thionyl chloride with straight-chain primary alcohols without presence or absence of pyridine.

In presence of pyridine:

ROH + SOCl2 → HCl + ROSOCl

HCl+C5H5N →C5H5NH++Cl

ROSOCl + Cl →RCl + SO2 (SN2)

ALSO READ:-

Important notes of Organic Chemistry for CBSE & JEE

Action of a phosphorus halide on the alcohol: ROH + PCl5 → RCl + HCl + POCl3.

By addition of Halogen to an alefins: R-CH=CH2 +Br2+CCl4 →R-CH(Br)CH2Br

Photohalogenation: CH4 + Cl2 +hv→ CH3Cl + HCl

Displacement of one halogen atom by another:RCl + NaI →RI + NaCl

Bonodine – Hünsdiecker Reaction: RCO2Ag + Br2→RBr + CO2 + AgBr

Hydrohalogenation of unsaturated hydrocarbons: In absence of peroxide: RCH=CH2 +HBr→RCH(Br)CH3

In presence of peroxide: RCH=CH2 +HBr + Peroxide →RCH2CH2Br

ALSO READ :-

Short notes of Quadratic Equation for IIT – JEE main & advance

Methods of Preparation of aryl halides

Halogenation: Ar-H + X2 +Lewis Base → Ar-x + HX

From diazonium salts:

  • C6H5N2Cl + HBF4 →C6H5F                         (Schiemann Reaction)
  • C6H5N2Cl + CuCl →C6H5Cl                         (Sandmeyer Reaction)
  • C6H5N2Cl + Cu powder →C6H5Cl            (Gatterman Reaction)

SN1 and SN2 mechanism:

ALSO READ :-

Short Notes of Complex Numbers for IIT-JEE mains and advance

Reactions of Alkyl Halides: Hydrolysis: : RX + OH → ROH + X

Williamson Synthasis: R-ONa +R’X → R-R’ + NaX

Reaction with dry silver oxide: 2R-X + Ag2O → R-O-R

Reaction with sodio-Alkynides: R-C≡C-Na +X-R→ R-C=C-R +NaX

Reaction with potassium-cyanide: KCN+X-R→ RCN +KX

Reaction with silver-cyanide: AgCN+X-R→ RNC +AgX

Reaction with silver-nitrite: AgNO2+X-R→ RNO2 +AgX

Reaction with potassium-nitrite: KNO2+X-R→ R-O-N=O +KX Fridal

Craft Reaction: R-X + C6H6 + AlCl3→C6H5-R

Malonic Ester Synthasis: R-X + -CH(CO2C2H5)2 →R-CH(CO2C2H5)2 +HX

Acetoacetic Ester Synthasis: R-X + -CH(CO2CH3)2 →R-CH(CO2CH3)2 +HX

MUST READ :- 

Tips and Tricks to crack JEE Mains in 2 months

Reaction with Ammonia: R-X +NH3→ R-NH2 +HX

Wurtz Reaction: 2R-I+ 2Na →R—R + 2NaI

Dehydrohalogenation: CH3.CH2.CH2Br + alco.KOH → CH3–CH = CH2 + KBr + H2O

Reaction with alcoholic AgNO3: R-X +AgNO3 → R+ + AgX↓+HNO3

Substitution Versus Elimination

ALSO READ:-

Short notes of Electro Chemistry for IIT-JEE Main and Advance

Haloform(Tri halide)

Preparation: It can be prepared from any alcohol having –CH(OH)CH3 group or from the aldehydes and ketones formed from above type of alcohols i.e, from a carbonyl compound having three a – hydrogen atoms by the action of X2 and an alkali or Na2CO3.

Laboratory Preparation of CHCl3

ALSO READ:-

Short Notes of Modern Physics for IIT-JEE mains and advance

Physical properties of CHCl3: colourless liquid with sweet smell and test. It is heavier than water and insoluble in it but soluble in alcohol and ether.

Chemical Reactions of CHCl3:

  • Oxidation: CHCl3 + 1/2 O2 → HCl + COCl2 (phosgene)
  • Hydrolysis: CHCl3 + 4NaOH → HCOONa + 3NaCl + 2H2O Carbyl
  • amine reactions: CHCl3 + CH3NH2 + 3NaOH →CH3N≡C +3NaCl +3H2O

    JEE Mains Crash Course offered by Eckovation

    To prepare for the JEE main Exam, one needs a platform where all their problems should be solved with clear concepts. At Eckovation, you will find the following:
    1. Chapter wise Notes
    2. Chapter wise Practice Papers
    3. Mock Tests
    4. All India Test Series
    5. Chapter wise Video Lectures
    6.All India Test Series
    7. Counselling
    8. Peer Discussion

    To Join the crash course and study with IIT Delhi Graduates: Click Here

Leave a Reply

Your email address will not be published. Required fields are marked *