Question

Change in the color of black tea on adding lemon juice is an example of _________ changes.

Answer 1

Adding lemon juice changes the acidity of tea.

Tea has polyphenol pigment $7-20\%$ and on adding acidic lemon juice, hydrogen ions suppress the ionization of polyphenols and that changes the color of tea making it lighter.

Therefore, the change in the color of black tea on adding lemon juice is an example of chemical change.