How tea is a natural indicator?

Tea, specifically black tea, acts as a natural indicator due to the presence of flavonoids, particularly theaflavins and thearubigins. These compounds change color depending on the pH of the solution they're in.

Here's how it works:

* Acidic solutions: In acidic solutions, like lemon juice, the theaflavins and thearubigins in black tea turn reddish-orange.

* Basic solutions: In basic solutions, like baking soda, the theaflavins and thearubigins turn dark green or brown.

Here's a simple experiment to demonstrate this:

1. Prepare three clear glasses: Fill one with water, one with lemon juice (acidic), and one with baking soda solution (basic).

2. Add black tea to each glass: Use a tea bag or strong brewed black tea.

3. Observe the color changes: The tea in the water will remain its usual dark brown color. The tea in the lemon juice will turn reddish-orange, while the tea in the baking soda solution will turn dark green or brown.

Therefore, black tea acts as a natural pH indicator, similar to litmus paper, allowing you to differentiate between acidic and basic solutions based on its color change.