CHE115 68 The puzzle: Cathy Coldridge is an aspiring NYC chef who works in a ver
ID: 1045351 • Letter: C
Question
CHE115 68 The puzzle: Cathy Coldridge is an aspiring NYC chef who works in a very busy kitchen in downtown Manhattan. Last week Cathy prepared a dish that contained boiled red cabbage. When she was draining the cabbage she noticed that the water color from clear and colorless to purple. Cathy was fascinated by this and decided to pour the colored water she had used to boil it in had changed r into 5 glasses that were lying around the kitchen to observe the color ly. When she poured the solution into the 5 glasses she was surprised to see the thy observed different color changes in each glass. color of the solution change AGAIN. Ca Her observations are summarized in the table below: Pt De Glass # Observation 1Solution turned pink/red Solution turned green Solution stayed purple Solution turned vellow 4 5 Solution turned blue Cathy is confused by these color changes and has come to you seeking help. 1. Identify the household chemicals that may remain in the bottom of each glass and hence cause the color of the solution to change. Quantify the acidity of each of these substances. 2. Rules of the game: 1. 2. 3. You must work on your puzzle in groups of 2 students. Each group will be given 1 leaf of red cabbage You have access to a selection of standard pH solutions and a selection of household substances. 4. You may not use more than 5 mL of any solution at a given time. Clues to help you solve the puzzle: 1. 2. 3. A standard pH solution is a solution of known pH. A pH indicator is a solution that changes color in response to changes in pH. To quantify the acidity of each substance you need to determine its pH value.Explanation / Answer
The component that gives purple colour to the red cabbage is Anthocyanin. it can be used as an Indicator.An indicator is a substance that changes the colour based on the acidity or alkalinity of the medium. Acids and alkalies are used in our daily life. for example, The lime juice we are using is citric acid,vinegar is acetic acid, Bleach is a stron base.
1)The colour obtained in diiferent glasses are based on the acidity and alkalinity of the substance present in the glass.
1) Pink/ red - because of the presence of Acetic acid . vinegar contains acetic acid.
2) solution turned green - because of the presence of a base, ammonia solution can turn red cabbage indicator green. ammonia is used in kichen cleaning solutions.
3)Solution stayed purple - the solution is nuetral. nothing affected the acidity or base of the medium. water is a nuetral solvent.
4) solution turned yellow - shows the presence of a strong base. Bleach is a strong base which contain sodium hydroxide
5) solution turned blue -shows the presence of a weak base like sodium bicarbonite. baking soda contains sodium bicarbonate.
2) The acidity can be quantified only if we know the pH of the solution. However we can predict the pH of the solution based on the colour they have shown in the red cabbage indicator. The coloured glasses containing substances are arranged based on their acidity.
a) Pink / Red - this indicates the pH - 2 to 3
b) purple solution - this indicates pH to 7
c) blue solution -this shows pH as 8 or 9
d) green solution - this is more basic than above solution ,so pH will be 12
e) yellow solution - this is because of the presence of a strong base and pH will be 14.
so with the intensity of colour produced we can predict the pH of the solution. acidic solutions show bright red to pink solutions and depending on the basicityof the solution turns colour to blue , green and yellow. Nuetral solution will not change colour. its stays as purple.