A. Phenolphthalein
A.
B. Litmus
B.
C. Methyl orange
C.
D. Bromothymol blue
D.
Correct Answer: B
সঠিক উত্তর: B
Explanation
ব্যাখ্যা
Examples of natural indicators include litmus, turmeric, and red cabbage. These indicators change color depending on whether they are in an acidic or basic solution.
Litmus:
This is the most commonly used natural indicator, extracted from lichens. It turns red in acidic solutions and blue in basic solutions.
Turmeric:
This spice also acts as a natural indicator, changing color from yellow to orange or red depending on the acidity.
Red cabbage:
The juice of red cabbage can also be used to determine acidity or basicity.