Question

Change in the colour of black tea on adding lemon juice is an example of ------- changes.

Answer 1

Hint: The answer for this question includes the basic concept of chemistry that explains which type of changes undergo in this type of reaction , whether physical or chemical change.

Complete step by step solution:
In the concept of chemistry in everyday life, we have come across the part where our body is made up of chemistry and the food we consume contains the chemistry concept.
- Accordingly, black tea is the one among which we consume in our daily life which is obtained from the shrubs of tea leaves naturally.
- The main components present in black tea are the polyphenol, amino acids and alkaloids.
- The polyphenol pigment for this black tea is about 7-20% and the addition of lemon juice to it changes the colour.
- This is because lemon juice is acidic in nature and when added to the black tea which is strong in nature gets lightened due to the suppression of hydrogen ions leading to the ionization of polyphenols which is responsible for colour change.
- Black tea has generally a stronger flavour compared to that of other tea. On adding lemon juice which is acidic, the colour changes to lighter because the acidity increases and the pH lowers down in this beverage.

Therefore, the correct answer is change in the colour of black tea by adding lemon juice as an example of chemical changes.

Note: The shortcut answer to this question can be guessed on the basis of the chemical nature of lemon and as it is responsible for colour change and this fact leads to the correct answer that it undergoes a chemical change.