Question

Turmeric is a natural indicator which turns:
A. yellow in acid and red in base.
B. yellow in base and red in acid.
C. blue in acid and red in base.
D. blue in base and red in acid.

Answer 1

Hint: In this question, first we have to know about the terms that are involved in the question. Chemical indicator, any substance that gives a visible sign, usually by a colour change, of the presence or absence of a threshold concentration of a chemical species, such as an acid or an alkali in a solution. An example is the substance called methyl yellow, which imparts a yellow colour to an alkaline solution.

Complete answer:

Turmeric contains a yellow-coloured chemical called curcumin, which is often used to colour foods and cosmetics. Turmeric is commonly used for conditions involving pain and inflammation, such as osteoarthritis. It is also used for hay fever, depression, high cholesterol, a type of liver disease, and itching.
Turmeric is also used as an natural indicator because turmeric changes its colour in the presence or absence of an acid or base.
The active ingredient present in turmeric is curcumin as an acid-base indicator that is yellow in acidic and neutral solutions and orange or reddish-brown in basic solutions.
Hence, we can say that turmeric turns yellow in acid and red in base.
Therefore, the option (A) is correct.

Note: In this type of questions, first we have to remember some basic points about the terms that are involved in the question. Then we have to find out the properties and nature of the substance given in the statement. After that we have to carry out the necessary property of the substance that is required to solve the question. Hence, we will get the answer.