Determination of the Concentration of Acid in Gastric Juice
Introduction
Titration is a method where a solution of known concentration is used to find the concentration of an unknown solution. A standard solution is a solution of precisely known concentration. The aim of this experiment was to go over the use of pipettes, burettes, titrations and also to reinforce the concept of molarity.
In this experiment, a titration was carried out using a standard solution of hydrochloric acid to establish the molarity of a solution of sodium hydroxide. The concentration of acid in the gastric juice sample was determined using that solution of sodium hydroxide. The pH of gastric juice was then calculated and compared with the value determined by …show more content…
The tap was opened and sodium hydroxide was slowly released into the conical flask while the flask was constantly swirled. The tap was closed when the slightest change in colour (pink) was visible.
The results were recorded and the experiment was repeated twice.
For the second titration, at step two 25 cm3 of gastric juice was used instead of hydrochloric acid. The pH of the gastric juice was measured using a pH meter.
Results
Table 1
Titration of 25 cm3 sodium hydroxide solution with 0.01 mol dm-3 hydrochloric acid
Initial burette reading (cm3) Final burette reading (cm3) Volume Used (cm3)
Rough Titration 0.00 25.0 25.0
First Accurate Titration 25.0 50.0 25.0
Second Accurate Titration 0.00 25.1 25.1
Average volume of sodium hydroxide solution used = 25.1 cm3
Number of moles of NaOH present in this volume = 0.01 x 25 / 1000 = 2.5x10-4
Therefore, molar concentration of NaOH = 1000 / 25.1 x 2.5x10-4 = 0.00996 mol dm-3
Table 2
Titration of 25 cm3 gastric juice with the standardised solution of sodium hydroxide
Initial burette reading (cm3) Final burette reading (cm3) Volume Used (cm3)
Rough Titration 0.00 31.0 31.0
First Accurate Titration 0.00 31.1 …show more content…
Therefore, a third titration was not
Introduction
Titration is a method where a solution of known concentration is used to find the concentration of an unknown solution. A standard solution is a solution of precisely known concentration. The aim of this experiment was to go over the use of pipettes, burettes, titrations and also to reinforce the concept of molarity.
In this experiment, a titration was carried out using a standard solution of hydrochloric acid to establish the molarity of a solution of sodium hydroxide. The concentration of acid in the gastric juice sample was determined using that solution of sodium hydroxide. The pH of gastric juice was then calculated and compared with the value determined by …show more content…
The tap was opened and sodium hydroxide was slowly released into the conical flask while the flask was constantly swirled. The tap was closed when the slightest change in colour (pink) was visible.
The results were recorded and the experiment was repeated twice.
For the second titration, at step two 25 cm3 of gastric juice was used instead of hydrochloric acid. The pH of the gastric juice was measured using a pH meter.
Results
Table 1
Titration of 25 cm3 sodium hydroxide solution with 0.01 mol dm-3 hydrochloric acid
Initial burette reading (cm3) Final burette reading (cm3) Volume Used (cm3)
Rough Titration 0.00 25.0 25.0
First Accurate Titration 25.0 50.0 25.0
Second Accurate Titration 0.00 25.1 25.1
Average volume of sodium hydroxide solution used = 25.1 cm3
Number of moles of NaOH present in this volume = 0.01 x 25 / 1000 = 2.5x10-4
Therefore, molar concentration of NaOH = 1000 / 25.1 x 2.5x10-4 = 0.00996 mol dm-3
Table 2
Titration of 25 cm3 gastric juice with the standardised solution of sodium hydroxide
Initial burette reading (cm3) Final burette reading (cm3) Volume Used (cm3)
Rough Titration 0.00 31.0 31.0
First Accurate Titration 0.00 31.1 …show more content…
Therefore, a third titration was not