Titration : Titration Of Hydrochloric Acid

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Lab:Titration Analysis of Hydrochloric Acid
In this lab a acid-base indicator phenolphthalein was used to determine endpoint of a reaction HCl(aq) and KOH(aq). At the end point all of the HCl(aq) would have reacted with KOH(aq), and the pH becomes 7. The phenolphthalein would changed colours from colourless to pink indication when enough KOH(aq) was added. The purpose of numerous trials was to use the average volume of the 3 trials with similar measurements.

The purpose of this lab was to use process titration to find concentration of an aqueous solution of Hcl(aq) , using KOH(aq) as the titrant.

Table 1.0: Information gathered during the trial: The volume of KOH(aq),titrant, used in different trial.

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Write a discussion of error summarizing 2 sources of error, why are your results and the other group different?
The first source of error that caused different results between group was that the groups misread the colour of the indicator at exactly the equivalence point. The other group could have misjudged light pink for clear and could’ve kept pouring the titrant till the color of the indicator changed dark pink ,which will result in a higher number of moles of the solution in your buret than in your flask. The extra moles of titrant used would give incorrect measurement since the amount KOH used would to titrate HCl would increase and giving a higher concentration for HCl. To avoid this source of error groups should used pH meter instead of phenolphthalein.A pH meter giver reading from 1-14 and doesn’t require judgment. The group would know solution is basic when the reading is 7 and they would stop pouring the titrant. This would avoid extra titrant in the solution and give a more accurate concentration.

The second source of error that caused different results

The method of titration was discovered in late 1800’s by a french pioneer name Francois Antoine Henri Descroizilles. Titration is a process used to find concentration of an unknown compound. This process is used in labs to find information need in everyday life.For instance, titration is used during blood test and urine test to determine the concentration
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