Methods of Preparation of Alkyl Halides

Question 1

Using Halogen Halide

What is Groove’s Process?

Lucas Reagent

Answer 1

Reaction of Alcohol with HCl in presence of anhy. ZnCl2 to give Alkyl Chloride and H2O

Hcl and ZnCl2 form Lucas Reagent

Question 2

Give order of reactivity of alcohol towards Hydrogen Halide

Pri, Sec, Tert.

Answer 2

3>2>1

Question 3

Using HBr

State special conditions required to form alkyl halide from Alcohol and HBr

Percentage of HBr, Catalyst

Answer 3

48% HBr
NaBr, H2SO4

Question 4

Using HI

What happens when alcohol is reacted with HI in presence of 95% Phosphoric Acid and NaI

Answer 4

ROH + HI => RI + H2O

Question 5

Using Phosphurus Halide

Give reation of ethyl alcohol with Phosphurus tri-iodide

Answer 5

3 CH3-CH2-OH + PI3 => 3 CH3-CH2-I + H3PO3

Question 6

Using Phosphurus Halide

What is the stability of different Halogens with PX5 and PX3

Answer 6

PCl3, PCl5 - Stable
PBr3, PI3 - Less Stable
PI5, PBr5 - Do not exist

Question 7

Reaction Of Alcohol with Thionyl Chloride

What products does cyclo-hexanol yeild upon heating with Thionyl Chloride

Answer 7

Cyclohexyl chloride, HCl (gas), SO2

Question 8

Preparation from Hydrocarbon

What happens when propene reacts with Hydrogen bromide

Answer 8

=> CH3-CH2-CH2-Br (Minor)

=> CH3-CH-CH3
|
Br

Question 9

Halogen Exchange

Give general reaction of “Finklestein Reaction”

explain

Answer 9

Allkyl Halide reacts with Sodium Iodide in presence of acetone to give Alkyl Iodide and Sodium Halide

Question 10

Halogen Exchange

Give general reaction for Swartz Reaction

Answer 10

RX + Metal Fluoride => RF + Metal Halide

Question 11

Swartz Reaction

What are the diff Metal Fluorides used in Swartz Reaction

Answer 11

AgF, Hg2F2, AsF3, SbF3

Question 12

Preparation of aryl halides

Under what conditions can aromatic compounds be converted to Aryl Halides

Answer 12

Reaction with halogens in presence of Fe conducted in DARK

Question 13

Why is Aromatic Electrophillic Substitution with Iodine reversible?

Answer 13

HI is a strong reducing agent. It converts aryl iodide back into arene.

Question 14

Explain Sandmeyer’s Reaction

Answer 14

When a primary aroatic amine, dissolved in cold, conc. mineral acid is treated with Sodium Nitrite, dizonium salt is formed.
Mixing soln of Dizonium salt with Cuprous Chloride (Cu2Cl2) replaces Dizonium grp with Cl

Dizonium grp N=N-Cl