Which of the following indicators are typically found as strips?

Litmus

The correct answer is option 3. Turmeric.

Litmus is a natural indicator that is commonly used in the form of strips or paper. Litmus paper is a convenient and easy-to-use pH indicator. It is made by impregnating paper strips with a solution of litmus, a water-soluble dye obtained from certain lichens.

Here is how litmus paper works:

1. Color Changes:  Litmus paper comes in two colors, blue and red. In its natural state, litmus is blue. When exposed to an acidic solution, the litmus paper turns red. In the presence of a basic solution, it turns blue again.

2. pH Indication: Litmus paper is sensitive to changes in pH. It is used to test whether a solution is acidic or basic. The color change is reversible, making litmus paper a simple and effective tool for qualitative pH testing.

3. Common Usage: Litmus paper is widely used in laboratories, educational settings, and various industries for quick assessments of the acidity or basicity of a solution. It provides a visual indication without the need for precise pH measurements.

While litmus paper is commonly found in strips, other indicators like phenolphthalein and bromothymol blue are also available in solution form. The choice of indicator depends on the specific requirements of the experiment or test being conducted.