LIMIT TEST FOR CHLORIDES

 

LIMIT TEST FOR CHLORIDES

 

 

AIM: To perform the limit test for chlorides in the given sample. APPARATUS REQUIRED: Nessler’s cylinders, glass rod, beaker and pipette.

CHEMICALS REQUIRED: Standard Sodium Chloride solution, dilute Nitric acid, 0.1 M Silver natrate solution and Hydrochloric acid.

PRINCIPLE: This test is designed for the control of chloride impurity in inorganic substances. It depends upon the precipitation of chlorides upon reaction with silver nitrate in the presence of nitric acid. The extent of precipitation depends upon the amount of silver chloride formed i.e. on the amount of chloride ions present in the substance. The opalescence produced was compared with a reference standard opalescence having a known amount of chloride impurity.

Cl^- + AgNO3                                  AgCl + NO3-

 

PROCEDURE:

 

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Take two Nessler’s Cylinders, wash th                                              Dil. HNO3nd then label as STANDARD and TEST

 

Preparation of Standard chloride solution: Accurately weigh 0.05845g of NaCl and dissolve in 100 ml of distilled water. (0.05845% w/v of NaCl).

Preparation of standard Solution:

 

Take 1 mL of NaCl solution and transfer into Nessler’s cylinder and add 10 ml dilute Nitric Acid and make up the volume up to 50 mL with distilled water then add 1 mL of silver nitrate solution. Stir well with a glass rod and keep it aside for 5 min.

 

 

Preparation of Test Solution:

 

Weigh a specified quantity of test sample and transfer into Nessler’s cylinder and add 10 ml dilute Nitric Acid and make up the volume up to 50 mL with distilled water then add 1 mL of silver nitrate solution. Stir well with a glass rod and keep it aside for 5 min.

SUMMARY:

 

STANDARD SOLUTION	Observation	Inference
In a Nessler’s cylinder Chloride std. solution (25ppm Cl) 10ml taken. Add 5ml water + 10 ml of dil.HNO3.
Dilute to 50 ml in Nessler’s cylinder + 1 ml of 0.1 M AgNO3 solution.
Stir & allow to stand for 5 min.   Observe the opalescence	The                opalescence produced in sample solution is greater than / less than that of standard solution.	The sample passes/ doesn’t pass the limit test for chlorides.
TEST SOLUTION
Specified substance (1gm) + 10 ml of water + 10 ml of dil.HNO3.
Dilute to 50 ml in Nessler’s cylinder + 1 ml of 0.1 M AgNO3 solution.
Stir & allow to stand for 5 min.
Observe the opalescence

 

The opalescence produced in the test solution is compared with that produced in standard solution.

 

 

OBSERVATION:

 

 

 

REPORT: The sample_              limit test for chlorides.