Limit Test Of Chloride- Lecture-1 4mc2f

MEDICINAL CHEMISTRY-I (PRACTICAL) Dr. SULTAN ALKALEH

LIMIT TESTS 1- LIMIT TEST FOR CHLORIDES (Cl-1)

LECTURE: 1

Aim: To detect chloride ions in some medicines products in the Yemeni marketing.

Forms of Chlorides: -Sodium chloride (NaCl), Sodium carbonate,………..etc.

Apparatus Required Glass cylinders 50ml: 2 Glass rod: 2 Stand: bench.

Chemicals Required Dilute Nitric acid (10% w/w): 20ml. (by using equation of N1XV1 = N2 X V2) Silver nitrate solution(5% w/v in D.W): 2ml. (Dissolve 0.1g of AgNO3 in 2ml of D.W) Sample: Unknown: ………………………… known: ……………………………

Principle The limit test for chlorides is based on its precipitation with silver nitrate in the presence of dilute HNO3, and comparing the opalescence produced due to the formation of AgCl with a standard opalescence achieved with a known quantity of Cl– ions. The equation may be expressed as :

NaCl + AgNO3  AgCl  + NaNO3

Procedure Take two 50 ml Nessler Cylinders. Label one as “Test” and the other as ‘Standard’.

Test

Standard

 Dissolve the specified quantity of the

Place 1ml of 0.05845% w/v solution of NaCl and transfer to Nessler cylinder.

substance in distilled water and transfer to Nessler cylinder. Add 10 ml of dil. HNO3. (Nitric acid). Dilute to 50ml with water in nessler cylinder. Add 1 ml of silver nitrate solution(AgNo3). Stir immediately with glass rod and allow

Add 10 ml of dil. HNO3. (Nitric acid). Dilute to 50ml with water in nessler

cylinder. Add 1 ml of silver nitrate solution(AgNo3). Stir immediately with a glass rod and allow to stand for 5 minutes. to stand for 5 minutes.  Observe the Opalescence/ Turbidity.  Observe the Opalescence/ Turbidity. The turbidity produced is not greater than the standard turbidity, when viewed transversely. Note: (Extent of turbidity depends upon the amount of chloride present).

Observation:

2nd Diploma & 4th Bachelor (Pharmacy)

1 ALJAZEERA UNIVERSITY – IBB - YEMEN

MEDICINAL CHEMISTRY-I (PRACTICAL) Dr. SULTAN ALKALEH

The opalegecence produce in sample solution should not be greater than standard solution. Then, the sample will the limit test of chloride and visa versa.

Reasons: Nitric acid is added in the limit test of chloride to make solution acidic and helps silver chloride precipitate to make solution turbid at the end of process.

2nd Diploma & 4th Bachelor (Pharmacy)

2 ALJAZEERA UNIVERSITY – IBB - YEMEN