Alfredo Verzo III
We have been provided with two samples of vinegar, one removed from a restaurant and one removed from a take-away. Trading Standards suspect these two establishments of watering down the vinegar. They need evidence that the samples contain less acid than the standard vinegar sample provided.
What is the purpose of this?
I’m a worker in the Trading Standards which carries out tests to see if restaurants and takeaways are watering down the vinegar. We will take one sample of vinegar from a restaurant and from a takeaway which we will carry out an experiment that will show us the results and concentration of the vinegar compared to the standard solution which Trading Standard provides.
What is a Vinegar?
Vinegar is a versatile liquid that is created from fermentation of ethanol, this is done by when yeast or any type of bacteria. These converts sugar in ethyl alcohol and carbon dioxide. Fermentation begins after the glucose enters the cell. The glucose is broken down into pyruvic acid and is converted into CO₂, ethanol and energy for the cell. It also contains acetic acid, this acid is the key ingredient because of this acid, and you can taste the acidic taste in the vinegar. Vinegar also contains different types of acid like tartaric, and citric, typical vinegar has a pH of 2 – 3.5. A standard table Vinegar contains about 4-8 percent of acid by volume Vinegar is mostly used for flavouring in food; by it also has medical, industrial and domestic use.
What percentage of which acid should a standard, ‘table vinegar’ solution contain?
A table Vinegar tends to be more diluted which can be 4/5% acetic acid and standard table Vinegar tends to be around 5% acetic acid (CH3COOH) which is also known as ethanoic acid. This is the chemical formula of acetic acid; ethanoic acid is diluted version of acetic. One molecule of acetic acid contains four hydrogen, two carbon and two oxygen atoms, this forms the chemical structure.
Why is it important that vinegar contains the correct concentration of acid?
It is very important that a vinegar contains the right concentration of acid, this is because if the company making the vinegar has a high concentration of acid in the vinegar it has a high potential of harm it can cause to the people would eat/drink this, they can seriously burn their inside which cause serious injury, or even enough to kill them, also if a vinegar is to diluted it would have no flavour therefore no one would taste the vinegar in the food. Trading Standards provides the information of the right concentration for companies would know what to do; this will avoid any problem, for example if they had the concentration of the acid to high, and it had injured a person. This is why there is a health and safety rules to be followed, for example the chemicals that they are using. must be disposed Trading Standard will perform an investigation and if the company was found guilty, there is a high chance that they will be fined, and if it was worse, the company has a chance of being shut down and put out of work.
What is a Titration?
A Titration is a technique where a solution of unknown concentration is identified by performing this test. A typical titration is where a titrant is added to a burette with the known amount of the unknown solution, until the reaction is complete. An acid-base titration is useful because acid-base titration techniques can help determine a pH of the chemical; also it allows us to see the lowest amount (in terms of volume) of a standardized substance you need to complete a reaction fully, which is why you add the substance slowly instead of quickly.
Explain the general theory behind an ‘acid-base’ titration
1. Using a pipette, measure out exactly 25cm3 of sodium hydroxide 2. Add about 2-4 drops of the indicator phenolphthalein to the alkali 3. Fill the burette to the...