Question

How to determine the purity of chloroform?

Answer 1

To test the purity of chloroform, shake some amount of it in a well stoppered bottle, along with the oil of vitriol (colourless) . If any trace of oils is found, the acid becomes yellow, and then allow it to stand, a darker line appears at the junction of the liquids. When the yellow colour appears, after being shaken and standing still for a short time, the chloroform is poured off into another vial, where it is shaken anew, with another and a smaller portion of vitriol. If, after some time, this appears colourless, the chloroform may be considered pure

Answer 2

Answer:

Physical test

Pure chloroform or CHCl₃ boils at 61-62°C. In case of impurities present, it will boil at a temperature higher than 62°C.

Chemical test

Reaction of chemically pure Chloroform with AgNO₃ will give a white precipitant of AgCl.

Explanation:

Physical purity

Chloroform is a colourless, transparent liquid. It boils at 62°C. In case any kind of impurity has been added to it, its boiling point will be higher than 62°C.

Chemical purity

To test the Chemical purity of chloroform AgNO₃ is used. Chloroform will produce phosgene gas and HCl on reaction with Oxygen. This HCl will react with AgNO₃ to form white precipitant, AgCl.

AgNO₃ + HCl ⇒ AgCl ( White ) + HNO₃