Volumetric analysis

Statistical volumetric analysis is a quantitative analytical technique that is widely used. The name implies that this method involves measuring the volume of a solution whose concentration has already been determined and then applying that information to determine the concentration of an analyte.

In other words, volumetric analysis or titration is the measurement of the volume of a second substance that reacts with a first substance in known proportions and is referred to as such. Our ability to determine the concentration of the analyte is based on this quantitative analysis technique. As part of his research into organic compounds, Jean-Baptiste-Andre Dumas developed and discovered the first method of Volumetric Analysis. He was attempting to determine the proportion of nitrogen combined with other elements when he came up with the method. A furnace was used to burn the nitrogen compound, which was then passed through a series of furnaces in a stream of carbon dioxide that was then passed into a strong alkali solution to ensure that the nitrogen compound was converted into pure gas. The nitrogen mass is calculated and the volume that it occupies under known conditions of pressure and volume from the sample is determined.

Procedure for Volumetric Analysis 

1)A typical titration begins with a beaker or flask containing a precise volume of the analyte and a small amount of indicator being placed beneath a calibrated burette or pipette containing the titrant, which is then filled with the titrant.

2)The solution that needs to be analysed must have an accurate weight in the sample of the material to be analysed of +/- 0.0001g of the material to be analysed.

3)Aspects of material analysis that are critical include selecting the appropriate type of titrant, as using the incorrect type of titrant will yield incorrect results. It is decided on a substance that reacts quickly and completely in order to produce a complete solution.

4)Increasingly small amounts of titrant are added to both the analyte and the indicator, and the indicator’s colour changes in response to the titrant saturation threshold, which indicates that the titration has reached its final destination.

5)There must be no interruption in the titration until the reaction is completed and the amount of reactant added corresponds exactly to the amount of reactant required to complete the reaction.

6)Since molarity is a standard metric for calculating the number of moles present in a solution, it is also critical to accurately measure the correct volume of the standard solution.

7)Single drops or less than a drop of the titrant can make the difference between a permanent and a temporary change in the indicator, depending on the desired endpoint.

8)Alternatively, if the reagent or reactant that we use is to be made into a standard solution, we can weigh and dissolve the reagent into a solution so that it is in a definitive volume within a volumetric flask.

Fundamental principles Volumetric analysis

1)Chemicals in the solution to be analysed are in an unknown amount in the solution.

In the presence of an indicator (most commonly phenolphthalein).

2)A reagent with an unknown concentration reacts with a chemical with an unknown amount to reveal the end-point concentration. It is the point at which the reaction is said to have come to a close.

3)Titration is used to determine the volumes because it allows the reaction between the solution and the reagent to be completed.

4)The amount of reagent and solution shown by the volume and concentration of reagent used in the titration is the amount of reagent and solution.

5)The mole fraction of the equation is used to calculate the amount of an unknown chemical present in a specific volume of water solution.

When the reaction reaches its endpoint, the volume of reactant consumed is measured and used to carry out volumetric analysis of the reaction product. The following formula is used to calculate the analyte concentration:

Ca= Ct Vt M / Va is a constant.

Where,

Ca represents the concentration of the analyte, which is typically expressed in molarity.

Ct denotes the titrant concentration, which is typically expressed in molarity.

V is the volume of the titrant that is used, which is usually expressed in litres.

M is the mole ratio of the analyte to the reactant as determined by the balanced equation.

V is the volume of the analyte, which is usually expressed in litres.

A large number of non-acid-base titrations are required to maintain a constant pH throughout the reaction. Because of this, a buffer solution can be added to the titration chamber in order to keep the pH constant.

Precautions

a) To obtain accurate results, it is necessary to take special care to thoroughly clean all of the equipment with distilled water. It is possible that even the smallest amount of any other chemical will cause errors in the final result.

b) When adding an acid or base, it is best to do so in small drops.

c) Contamination should be avoided to the greatest extent feasible.

d)If you are taking readings, make sure that the markings are at eye level while you are doing so.

e)It is necessary to use the lower meniscus when dealing with colourless solutions, whereas the upper meniscus should be used when dealing with coloured solutions.

f) The index finger should always be used when pipetting any solution.

g)It is important to check that the burette is not leaking and that there are no air bubbles trapped inside it. 

h)It is also important to note that the indicator should never be used excessively.

i)Take extra care when filling the pipette in order to obtain accurate results.

Conclusion

Statistical volumetric analysis is a quantitative analytical technique that is widely used. The name implies that this method involves measuring the volume of a solution whose concentration has already been determined and then applying that information to determine the concentration of an analyte.A typical titration begins with a beaker or flask containing a precise volume of the analyte and a small amount of indicator being placed beneath a calibrated burette or pipette containing the titrant, which is then filled with the titrant.The solution that needs to be analysed must have an accurate weight in the sample of the material to be analysed of +/- 0.0001g of the material to be analysed.Chemicals in the solution to be analysed are in an unknown amount in the solution.

In the presence of an indicator(most commonly phenolphthalein).To obtain accurate results, it is necessary to take special care to thoroughly clean all of the equipment with distilled water. It is possible that even the smallest amount of any other chemical will cause errors in the final result.