Turmeric: Indicator :: Milk of magnesia: Antacid

Explanation:

Indicators:
Indicators are substances that help us determine whether a substance is acidic or basic. They change color depending on the pH of the solution they are added to. Turmeric is a natural indicator commonly used in laboratories to test for the acidity or basicity of a solution. It turns reddish-brown in acidic solutions and yellow in basic solutions.

Milk of Magnesia:
Milk of magnesia is a suspension of magnesium hydroxide in water. It is commonly used as an antacid to relieve heartburn, indigestion, and upset stomach. Antacids work by neutralizing excess stomach acid, reducing the acidity in the stomach, and providing relief from discomfort.

Analogy Explanation:
The analogy presented in the question is between turmeric and indicator, and milk of magnesia and antacid. The relationship between the two pairs is that turmeric is a type of indicator, and milk of magnesia is a type of antacid.

Turmeric as an Indicator:
Turmeric contains a compound called curcumin, which exhibits pH-sensitive color changes. It is commonly used as a natural indicator in chemistry experiments. When turmeric is added to an acidic solution, the curcumin reacts with the hydrogen ions present and changes color to reddish-brown. In a basic solution, the curcumin does not react and remains yellow.

Milk of Magnesia as an Antacid:
Milk of magnesia is primarily composed of magnesium hydroxide, which is a weak base. When it is ingested, milk of magnesia reacts with the excess hydrochloric acid in the stomach. The magnesium hydroxide neutralizes the acid, forming magnesium chloride and water. By reducing the acidity in the stomach, milk of magnesia helps alleviate symptoms of heartburn, indigestion, and upset stomach.

Conclusion:
The correct answer is option B: Antacid. Just like turmeric is a type of indicator, milk of magnesia is a type of antacid. Turmeric helps determine the acidity or basicity of a solution, while milk of magnesia neutralizes excess stomach acid.