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Q.
$ CHCl_{3} $ is tested prior to its use as anaesthetic, by:
Rajasthan PMTRajasthan PMT 2004
Solution:
Chloroform is tested by $AgNO _{3}$ before its use as anaesthetic because chloroform is oxidised by atmospheric air to a poisonous gas phosgene (carbonyl chloride) on standing for sometime. In this reaction, it also form $HCl$ which give white ppt. with $AgNO _{3}$. Hence, chloroform is used only when it does not form white ppt. with $AgNO _{3}$.
$CHCl _{3}+ AgNO _{3} \longrightarrow \times$ No reaction
$CHCl _{3}+ O \longrightarrow \underset{\text { Poisonous }}{COCl _{2}}+ HCl$
$HCl + AgNO _{3} \longrightarrow \underset{\text { White }}{ AgCl }\downarrow+ HNO _{3}$