1. Classification of Volumetric Methods 1. Acid-base 2. Precipitation 3. Complexometric 4. Reduction-oxidation (Redox

2. Acid-base May compounds, both inorganic and organic, are either acids or bases, and can be titrated with a standard solution of a strong base or a strong acid. The end points of these titrations are easy to detect, either by means of an indicator or by following the change in pH with a pH meter.

3. The acidity and basicity of many organic acids and bases can be enhanced by titrating in a non aqueous solvent. The result is a sharper end point, and weaker acids and bases can be tirtrated.

4. Standard Solution A standard solution is a solution of exactly known concentration.

5. Standardization Factor (F) It is the number by which the actual volume of the solution of approximate strength must be multiplied to obtain the equivalent volume of a standard solution of exact normality. It is calculated by dividing the actual or practical normality by the theoretical normality.

6. F = Actual ( practical) normality Theoritical normality

7. Standardization of 0.05 N HCl (Using Primary Standard Na 2 CO 3, and Calculation of Standardization Factors (F) Principle Na 2 CO 3 + 2 HCl → 2 NaCl + H 2 O + ↑CO 2 Indicator is methyl orange (M.O.)

8. Procedure 1. Pipette 5 ml of 0.1 N Na 2 CO 3 solution in a conical flask. 2. Add 2 drops of M.O. indicator (color change from yellow to orange). 3. Titrate with HCl (to be standardized). EP is orange color. 4. Repeat titration two times and record your result.

9. F = Actual ( practical) normality Theoritical normality Calculation N 1 V 1 = N 2 V 2 Practical normality N 2 for HCl = N 1 V 1 V 2 For Na 2 CO 3 for HCl V 2 = EP

10. Standardization of 0.1 N NaOH Principle NaOH + HCl → NaCl + H2O Procedure 1. Pipette 5 ml of 0.1 N NaOH solution into a 250 ml conical flask. 2. Add 2 drops of ph.ph indicator. 3. Titrate with the previously standardized 0.05 HCl, color change from pink to coulerless.

11. Calculation N 1 × F × V 1 = N 2 × V 2 (HCl) (NaOH) N2 (for NaOH) practical normality N 1 × F × V 1 V 2 V 1 = EP. Standardization factor for NaOH = Actual ( practical) normality Theoritical normalit y