Exercise No. 10 ASSAY OF ASPIRIN TABLETS Assay procedure: Residual alkalimetric with blank titration Standard solution: 0.1N Sulfuric acid Primary Standard: 0.1 N sodium hydroxide Indicator: Phenolphthalein TS Chemical reactions: (NH4)3PO4-12MoO3-H20 + 23 NaOH 11Na2MoO4 + (NH4)2 MoO4 + 12H2O Endpoint color: Permanent pink color

Procedure 1. Weigh finely powder not less than tablets. 2. Transfer an accurately weighed amount of powdered tablets equivalent to 100mg Aspirin in a 500 mL Erlenmeyer flask to compute for the amount of sample equivalent to 100 mg of Aspirin. Use ratio and proportion 3. Add 15ml of neutralized alcohol and mix for five minutes. 4. Then add three drops of phenolphthalein and titrate with 0.1 N sodium Hydroxide until pink color is produced. 5. Add to the titrated solution a volume of 0.1 sodium hydroxide equal to that used in the titration plus 15 ml more, heat the mixture in a water bath for 15 minutes with frequent agitation using an air condenser. Remove the flask from the water bath and cool it quickly at room temperature. 6. Titrate with 0.1 N Sulfuric acid solution until the pink color disappears. 7. Perform the blank determination.

PREPARATION AND STANDARDIZATION OF TENTH-NORMAL(0.1) SILVER NITRATE Exercise No. 11 Exercise No. 11 PREPARATION AND STANDARDIZATION OF TENTH-NORMAL(0.1) SILVER NITRATE

Assay procedure: Precipitation method Exercise No. 11 PREPARATION AND STANDARDIZATION OF TENTH-NORMAL(0.1) SILVER NITRATE Assay procedure: Precipitation method Primary Standard: Sodium Chloride Indicator: Eosin Y TS Chemical reactions: AgNO3 + HCl AgCl +HNO3 Endpoint color: Purplish color

Preparation and Standardization 1. Transfer 100 mg sodium chloride (dried at 110’C For 2 hrs) 2. Dissolve in 5ml nitric acid + 50 ml methanol 3. Add 3 drops Eosin Y TS. STANDARDI ZATION Weigh 4.375 g Silver nitrate crystals Add 250 ml distilled water Titrate with silver nitrate solution.

Exercise 12 PREPARATION AND STANDARDIZATION OF TENTH-NORMAL(0 Exercise 12 PREPARATION AND STANDARDIZATION OF TENTH-NORMAL(0.1) SILVER NITRATE

Assay procedure: Direct titration under precipitation method Exercise No. 12 PREPARATION AND STANDARDIZATION OF TENTH-NORMAL(0.1) AMMONIUM THIOCYANATE SOLUTION Assay procedure: Direct titration under precipitation method Standard solution: 0.1N Ammonium Thiocyanate Indicator: Ferric alum End point color: Red brown color solution Reaction: AgNO3 + NH4SCN AgSCN + NH4NO3

Schematic diagram: Procedure 15ml of 0.1N silver nitrate placed in erlenmayer flask Dilute with 25ml distilled water add 1ml nitric acid 1ml Ferric alum (indicator) titrate with standard solution untill red-brown color appears

EXERCISE N0. 13 ASSAY OF SODIUM CHLORIDE CONTENT OF IODIZED SALT

EXERCISE N0. 13 ASSAY OF SODIUM CHLORIDE CONTENT OF IODIZED SALT Assay procedure: Volumetric Residual Precipitation Method (Volhard Method) Standard solution: O.1N Silver nitrate Second Standard solution: 0.1N sodium thiocyanate Indicator: Ferric alum Analyte: Iodized salt solution End point color: Red brown colored solution Reaction: NaCl + AgNO3 AgCl + NaNO3

2ml ferric alum (indicator) Schematic diagram 1. 300mg of iodized salt 2. 50ml distilled water 3. 50ml of 0.1 silver nitrate 4. 3ml nitric acid 5. 5ml nitrobenzene 6. 2ml ferric alum (indicator) 7. Titrate with excess silver nitrate with standard solution until red brown color appears.

Exercise No. 14 ASSAY OF AMMONIUM BROMIDE

Exercise No. 14 ASSAY OF AMMONIUM BROMIDE Assay procedure:Residual Precipitation Method Standard solution: 0.1N silver nitrate Second Standard Solution: 0.1 N Ammonium Thiocyanate Indicator: Ferric alum TS Analyte: Aspirin in neutralized alcohol End point color: Reddish-brown colored solution Reaction:

Schematic diagram 1. 300mg ammonium bromide 2. Dissolve in 50ml distilled water 3. 50ml 0.1N silver nitrate from buret 4. 2ml ferric alum (indicator) 5. 2ml nitric acid

Mrs. Junabeth Cervantez Presented by: DAGURO, Aprilyn DOMALINA, Mae Realene JUAN, Monicka MACAYANAN, Romina R. PASCUAL, Kris Submitted to: Mrs. Junabeth Cervantez