Lab Analysis Of An Acid-Base Titration

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1.1What is an acid-base titration?

An acid –base titration is the determination of the concentration of an acid or base by neutralizing the acid or base with an acid or base of known concentration.

An acid-base titration is the analysis of the concentration of acids and bases; through this process an acid or base of known concentration neutralizes an acid or base of unknown concentration.

The neutralization of an acid or base in acid-base titration can be measured with either a color indicator or a pH-meter. For this experiment we are using a color indicator.

The indicator phenolphthalein is used in experiment 1 and starch was use as an indicator in experiment 2.Phenolththalein is a colorless in acidic solution and pink in
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The mixture in 2 was titrated against sodium thiosulfate placed in a 50.00 mL burette.

4. Steps 1-4 was repeated untill a difference of 0.01 mL is noticed in values taken.
Experiment 1:
Titration is a common laboratory method of quantitative chemical analysis that is used to determine the unknown concentration of an identified analyte. IN our case, it is an acid-base titration.
In the titration the titrant(solution with a known concentration of reagent) is added to the analyte through a burette untill the reaction is completed. The titration isterminated when the end-point is reached. The end-point is normally noticed by a rapid change in color of the solution.
This type of reaction also known as neutralization reaction which means formation of water. It normally occurs at pH 7.
Experiment 2:
The aim of standardizing a solution of sodium thiosulfate pentahydrate is to find its exact concentration from the approximate given value.
On titrating, the color changes from colorless to pale yellow and only then 2 drop of starch is added to the solution to become dark blue.
The reason why starch was added close to the end point is to prevent the production of starch-iodine complex over time.
2.1Results and
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The average of volume of NaOH used in the calculations was calculated as the average of the two best values which increases accuracy.
The final pH of the titration can be altered if excess indicator is a added.
Experiment 2:

To prepare the solution of KIO3, the mass that must be added in 250 mL of distilled water must be calculated as shown; 1 mol of KIO3 is contain in 214.00g 0.005 mol of KIO3 1.07g Since the potassium iodate is only 99% pure 99% 1.07g 100% 1.081g
Hence, mass of KIO3 used= 1.081g

Apart from KIO3 and KI, sulfuric acid is also present in the conical flask, in excess, to provide H+ ions to increase the rate of reaction. 2.3 Conclusion

After having done both experiment in the laboratory, we can conclude that he titration method relying on visual detection of the end point for quite precise determination of the unknown

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