Summary
Summary Unit 13 Assignment A
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Qualification Distinction Pearson BTEC Level 3 National Diploma in Applied Science Pearson BTEC Level 3 National Extended Diploma in Applied Science
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When subjected to a certain pH range, each of these indicators takes on a particular colour,such as phenolphthalein, which becomes colourless when exposed to a pH range of 8 to 10.
Despite using an indicator is the most accurate method to determine whether the pH has
changed, there is a significant amount of room for error, and relying solely on colour alone
can be risky because it isn't very precise. It is also advised to use a pH metre when trying to
determine a solution's pH because the indicators change when the solution is in a wide pH
range. We used phenolphthalein, as demonstrated in the prior experiment, and slowly added
the titrate solution while watching for a shift in colour. However, when mixed, the colour
would occasionally shift and then come back, or shift but only in a small part of the solution
before going away. It was difficult to tell when the shift had happened, suggesting that
sometimes too little or too much was added, unfairly biassing the experiment. It would be
wasteful for technicians to perform daily titrations in large laboratories, so instead, auto-
titrators are used. While this eliminates the possibility of human error, it also means that
every titration would release the same amount of liquid, which could be either too little or too
much, which the auto-titrator would not be able to detect. An auto titrator also lacks the
ability to swirl the flask or beaker during the titration, which is something a person would do
to ensure that the indicator, acid, and base are properly mixed in. The titration failed because
the liquid could not change colour when it was genuinely spun around. The correct indicator
must be used when performing an acid-base titration; phenol red is the incorrect indicator. On
the other hand, thymol blue only altered colour when the pH was between 1.2 and 2.8. The
costs of conducting research outside of a lab setting can add up fast. They must all be precise
for them to work correctly, in other words. The costs can rapidly mount when conducting
research on a larger scale than in a lab. To achieve the intended results and prevent financial
waste, they must all be exact.
Costs result from things like:
To obtain precise results, all the equipment used have undergone calibration.
The maintenance of the machinery to make it functional and up to date.
This might make the titration process take longer as it is possible for calibration errors to
occur, it is vital to repeat the titration to identify anomalies and obtain a more accurate result.
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