What changes colour do you observe when turmeric mixes with a base?

Turmeric is a spice that is commonly used in cooking. It has a bright yellow colour when it is dry, but when it is mixed with a base, it turns a deep red colour. This is because turmeric contains a chemical called curcumin, which is a natural dye. Curcumin is a polyphenol, which means that it contains multiple hydroxyl groups. These hydroxyl groups react with the hydroxide ions in the base to form a red colour.

The change in colour that occurs when turmeric is mixed with a base is a chemical reaction that is known as an acid-base reaction. In an acid-base reaction, an acid donates a proton (H+) to a base. The hydroxide ions in the base react with the protons from the turmeric to form water molecules. This reaction also causes the curcumin molecules to rearrange themselves into a different shape, which is what gives them their red colour.

The change in colour that occurs when turmeric is mixed with a base can be used to test for the presence of acids and bases. If a substance turns turmeric red, it is a base. If a substance turns turmeric yellow, it is an acid. This test can be used to identify different types of chemical compounds.

The change in colour that occurs when turmeric is mixed with a base is also used in some traditional Indian cooking. For example, turmeric is used to dye rice a yellow colour. It is also used to make a red colour for Holi, a Hindu festival of colours.