Chemistry Laboratory Research

In this study, the titration was once carried out using dilute Hydrochloric Acid on the burette and an alkali (Potassium hydroxide) of known awareness of 0.05Mol dm-3. The aim of the report is to decide the concentration of dilute Hydrochloric acid, analyze the results of the acid-base titration, and lift out systematic error calculations based on the apparatus used. In carrying out the calculations, the standardized alkali is the foundation of the calculations since the concentration is already described (Kahlert et al. 16).

Consider the results or burette readings in the table below,

Average titre = 22.10cm³

In order to calculate the concentration of dilute Hydrochloric acid, we need to have the equation for the reaction and determine the number of moles of potassium hydroxide (Kahlert et al. 23). From the number of moles of potassium hydroxide we can use the mole ration to find the number of moles of the hydrochloric acid used.

The balanced equation for the reaction is;

HCl (aq) + KOH (aq) ­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­                            KCl (aq) + H2O (l)

The mole ratio of Hcl : KOH id equal to 1:1, this means that the number of moles of dilute Hydrochloric acid used is equivalent to the number of moles of Potassium hydroxide used.

The number of moles of Potassium hydroxide;

1000cm³ of KOH, contains 0.05 moles

This means, 1cm³ of KOH contains, 0.05/1000 moles

Therefore, 25cm³ of KOH will contain, 0.05/1000*25 moles = 0.00125 moles

From the number of moles of KOH and considering the mole ratio of 1:1, the moles of HCl acid is therefore = 0.00125 moles.

The concentration of HCl acid is got from considering the average titre used, 22.10cm³.

Therefore, 22.10cm³ of HCl acid contains 0.00125 moles, the concentration is, 0.00125*1000/22.10 = 0.0567 mol/dm³, this is approximately = 0.06 mol/dm³

The analysis of the results is geared towards determining the percentage difference and the Systematic error (Kahlert et al. 19).

The percentage difference = difference between the 2 values*100/technician value

                                           = 0.06-0.05*100/0.05

                                       = 20%

Systematic or apparatus error = error of the equipment *100/amount measured

Error for the burette = 0.1*100/50 = 0.2%

Error for pipette = 0.06*100/25 = 0.24%

Total Apparatus Error = 0.24 + 0.2 =0.44%

Therefore, Random error = Difference-total apparatus error

                                          = (20-0.44) %

                                            =19.56%

The value got in the calculation is 19.56% error, this is a large value in terms of the error. In this regard, the results are not a 100% accurate. The value got is beyond the expected value due to a number of errors. The errors could be due to; inaccurate measurement of volumes of the solutions, poor reading of the meniscus due to parallax error, and inability to correctly notice the color changes at the endpoint (Kahlert et al. 10).

Work Cited

Kahlert, Heike, Gabriele Meyer, and Anja Albrecht. "Colour maps of acid–base titrations with colour indicators: how to choose the appropriate indicator and how to estimate the systematic titration errors." ChemTexts 2.2 (2016): 1-28.