Acid Base Titration

This week, we revisited the subject of acids and bases. As defined by the Bronsted-Lowry duo, an acid is a substance that donates protons, and a base is a substance thats acceptors protons. These “protons” are, in other words, hydrogen ions. All acid-equations have hydrogen present, due to the acid in the equation. In the case of strong acid base reactions, water is always produced, and it is the driving force of the reaction.

Titration is an analytical technique in which one can calculate the concentration of a solute in a solution. This concentration is determined by using a known solvent and an indicator. Frequently, it is utilized for performing acid/base neutralizations. During this process, a known substance, or titrant, is slowly added to an unknown solution until neutralization occurs. An color indicator is used to exhibit at what moment the solutions neutralize.

In our lab, we were tasked with empirically determining the concentration of a sample of hydrochloric acid. To do this, we created 1M NaOH, and then used a bulb and a pipette to transfer 20 mL of the hydroxide to an Erlenmeyer flask. Then, indicator drops were added, followed by the addition of unknown molarity HCl via a buret until neutralization occurred. The change of the indicator color from hot to light pink meant that the solutions had been neutralized. Using the amount of HCl needed to neutralize the reaction, molarity of HCl can be calculated. If multiple trials are performed, as was our case, the molarities can be averaged for a more accurate number.


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