Physical And Chemical Property Of Haloalkanes.

By Anup Pokhrel

The physical property of Haloalkanes.

  1. . State.
  2. Solubility.
  3. Boiling point.
  4. Density.

State.

  1. lower haloalkanes are gases.
  2. C2-C8 haloalkanes are colourless sweet smelling liquid.
  3. Higher haloalkanes are colourless.

Solubility.

Even if haloalkanes are polar compound they are insoluble in water due to their incapability of forming hydrogen bonds with water molecules.

R+XR+−X−
PalarityinhaloalkanesPalarityinhaloalkanes

They are, however, soluble in the organic solvent like benzene, chloroform, (CHCl)3 carbon tetrachloride.

3. Boiling points.

RX>RHR−X>R−H

Haloalkanes boil at a higher temperature than corresponding alkanes.

Moreover, their boiling points increase with an increase in their molecular weight.

CH3I>CH3Br>CH3Cl/CH3CH2CH2Cl>CH3CH2Cl>CH3ClCH3I>CH3Br>CH3Cl/CH3CH2CH2Cl>CH3CH2Cl>CH3Cl

Among the isomeric haloalkanes, the linear isomer boils at a higher temperature than any other branched isomer.

Chemical Properties.

1. Nucleophilic substitution reaction.

Nucleophiles are the species having either negative charge (Cl-, Br-, NO2-, CN-, OH-, Ro- etc). or containing the lone pair of electron.

Due to the difference in electronegativity of carbon and halogen, C-X bond of haloalkane develops a polar character in which carbon is partially positive and halogen is partially negative. An incoming nucleophile can easily attack at the very +Vely charged carbon thereby substitutinghalide ion.

Some typical nucleophilic reaction of haloalkanes.

Reaction with water.

Haloalkane when reacts with water it gives Alcohol.

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