Physical And Chemical Property Of Chloroform. Class 12 Chemistry Nepal

Physical property.

Some of the physical property are as follows.

It is colourless and sweet smelling liquid.
Freezing point and a boiling point of chloroform are -63⁰C and 61⁰C.
It is non-flammable liquid. However, vapour chloroform burned with the green flame.
It is insoluble in water and soluble in organic solvent.
Although chloroform is non-poisonous, if forms a poisonous compound (phosgene) in air.

Chemical property.

Some of the chemical property are as follows.

1. Oxidation reaction.

Chloroform is oxidised in the air in presence of sunlight to form a poisonous compound called phosgene.

2 C H C l 3 + O 2 (a i r) -\to---- S u n l i g h t 2 C O C l 2 + 2 H C l

Chloroform is stored in a dark brown bottle with a tight lid so as to prevent the formation of poisonous phosgene.

Chloroform containing bottle is often supplied with a small amount of ethanol since it converts phosgene into diethyl carbonate which is non-poisonous.

2. Reduction.

Chloroform is reduced to dichloro methane in acidic and neutral medium respectively.

C H C l 3 + 2 [H] -\to---- Z n / H C l C H 2 C l 2 + H C l

C H C l 3 + 6 [H] -\to---- Z n / H 2 O C H 4 + 3 H C l

3.Hydrolysis.

Chloroform on boiling with aqueous KOH hydrolyzed to form potassium formate.

C H C l 3 + 4 K O H -\to-- H e a t H C O O K + 3 K C l + 2 H 2 O

4. Chlorination.

Chloroform on further chlorination gives carbon tetrachloride.

C H C l 3 + C l 2 -\to h v C C l 4 + H C l

5. Action with nitric acid.

Chloroform on heating with concentrated nitric acid forms chloropicrin which is used as an insecticide and war gas.

C H C l 3 + H N O 3 -\to-- H e a t C C l 3 N O 2 + H 2 O

6. Action with silver powder.

2CHCl_3+6Ag\xrightarrow{Heat}HC≡CH+6AgCl$$

7. Reaction with Phenol. (Reimer -Tiemann reaction).

When phenol is heated with chloroform and aqueous alkaline at temperature 60-70⁰C, O-hydroxy benzaldehyde (Salicylaldehyde) is formed as the chief organic product. This reaction is termed as Riemer-Tiemann reaction.

8. Reaction with the primary amine.

(Carbylamine reaction)

Chloroform produces an offensive smelling carbylamines or isocyanide when warmed with the Primary amine (R-NH2-aliphatic or aromatic) in presence of an alkali. This reaction is known as carbylamines reaction.

A haloalkane P reacts with aq. KOH to give Q. The compound Q on oxidation with K₂Cr₂O/H⁺ give R and R undergo Clemmensen reduction to produce S. The compound P reacts with sodium in presence of dry ether to form 2,3 dimethylbutane, Write chemical reactions involved and identify P,Q,R and S.

Answer.

Let identify P at first reacts with sodium metal in the presence of dry ether to give 2,3 dimethylbutane so P should be 2- Haloproparopane.

Physical And Chemical Property Of Chloroform.

Physical property.

Chemical property.

Discussion