**Turmeric as a Natural Indicator**

Turmeric, a commonly used spice in cooking, can also be used as a natural indicator to detect the presence of bases. The active compound in turmeric responsible for this property is called curcumin. When curcumin comes into contact with bases, it undergoes a chemical reaction that results in a change in color. In the presence of bases, turmeric turns bright red.

**Explanation**

Turmeric contains a class of compounds known as polyphenols, which are responsible for its vibrant yellow color. Curcumin, one of the polyphenols present in turmeric, acts as a pH indicator. pH indicators are substances that change color depending on the acidity or alkalinity (basicity) of a solution.

Bases are substances that can accept protons or donate hydroxide ions (OH-) in a chemical reaction. When a base is added to a solution of turmeric, the curcumin molecules react with the base, resulting in the formation of a new compound. This new compound has a different structure and absorbs light in a different range of wavelengths, giving rise to a change in color.

In the case of turmeric, the reaction with bases leads to the formation of a red compound. This compound is responsible for the bright red color observed when turmeric comes into contact with bases. The exact mechanism of this reaction is complex and involves multiple steps, including the deprotonation of curcumin and the formation of a conjugated system.

**Conclusion**

In conclusion, turmeric can be used as a natural indicator to detect the presence of bases. When turmeric is exposed to bases, it undergoes a chemical reaction that results in a change in color. The active compound in turmeric, curcumin, reacts with bases to form a red compound, giving turmeric a bright red color in the presence of bases.

See it is actually a chemical reaction.. We all know that turmeric contains tartaric acid in it and base(for eg Naoh) contains sodium hydroxide reacts together which ultimately led the colour to change from yellow to red... that's it...