what happens when an acidic solution is added to turmeric
Answers
Turmeric is a plant whose parts are often used as a spice in cooking. Turmeric is an example of a natural pH indicator, which means that it can be used to determine a substance’s pH.
The pH of a substance is its level of acidity or alkalinity. To be more precise, pH is a measure of the concentration of hydrogen ions (H+) relative to hydroxide ions (OH-) in a substance. The range of pH values is represented on a logarithmic scale from 1 to 14. If a solution contains more hydrogen ions than hydroxide ions it is considered acidic and will have a pH between 1.0 and 6.9. However, if there are more hydroxide ions than hydrogen ions, the solution will be alkaline and will have pH between 7.1 and 14. If the amounts of hydrogen ions and hydroxide ions are equal - such as in pure water - the solution is considered neutral and has a pH of 7.0.
Indicators, such as turmeric, work by changing their colour with changes in pH. There are many different pH indicators and each indicator changes colour at a particular pH level. Often an individual indicator will only undergo one or two colour changes. This usually means that using a single pH indicator will tell you the general pH range of an unknown solution. Usually several different indicators must be used and the results compared in order to accurately determine the pH.
The turmeric indicator changes colour between roughly a pH of 7.4 and 8.6. If turmeric is exposed to neutral or acidic substances (those with a pH of less than 7.4) it will retain its yellow colouration. However, if turmeric is exposed to more alkaline substances (those with a pH greater than 8.6) it becomes a dark pink/red.
Bicarbonate of soda solution is alkaline so the turmeric-dyed toilet paper turned from yellow to dark pink/red when it was dipped in the bicarbonate of soda solution. Vinegar is acidic so the turmeric-dyed toilet paper turned from dark pink/red to yellow when it was dipped in the vinegar.