Question

Chloroform for anaesthetic purposes is tested for its purity with the reagent
A. Silver nitrate
B. Lead nitrate
C. Ammoniacal \[C{u_2}C{l_2}\]
D. Lead nitrate

Answer 1

Hint: The chemical formula of chloroform is \[CHC{l_3}\]. Chloroform in its pure state does not ionise due to the carbon-chlorine covalent bonds. The chloroform that is used for anaesthetic purposes is not in its pure state.

Complete Step by Step Solution:
The other name of chloroform is trichloromethane. It has an ether-like odour. It is used as an anaesthetic during surgery but apart from its anaesthetic ability, it is used as a solvent in many industries from the preparation of other chemicals, papers, refrigerants, wax, fats, and oil.

Chloroform is the by-product of water chlorination therefore chloroform is present in low amounts of chlorinated water.

High inhalation of chloroform leads to impaired liver function, nausea, cardiac arrhythmia, and dysfunction of the central nervous system.

The purity of chloroform is tested by reacting it with a cold solution of silver nitrate. Chloroform in presence of oxygen forms phosgene and hydrochloric acid. The silver nitrate solution reacts with the hydrochloric acid to form the white precipitate of silver chloride.

The reaction is shown below:
\[CHC{l_3} + \dfrac{1}{2}{O_2} \to HCl + COC{l_2}\]
In the above reaction one mole of chloroform reacts with half mole of oxygen to give one mole of hydrochloric acid and one mole of phosgene.
\[AgN{O_3} + HCl \to AgCl + HN{O_3}\]

In the above reaction, one mole of silver nitrate reacts with one mole of hydrochloric acid to form one mole of silver chloride and one mole of nitric acid.
Therefore, the correct option is A.

Note: To prevent the formation of phosgene, the chloroform is stored in a dark-coloured bottle. Phosgene is very toxic in nature.