Curcumin Properties and Reactions

The video tutorial explores the properties of curcumin found in sunflower dye. It demonstrates curcumin's solubility in non-polar solvents like acetone and its limited solubility in polar solvents like water. The addition of a base allows curcumin to dissolve in water by forming an ion. Curcumin's fluorescence under UV light is observed, and its acid-base indicator properties are tested across various pH levels. Finally, the reaction of curcumin with borates to form a rose-colored complex is demonstrated.

What is the main component in sunflower dye that affects its solubility in non-polar solvents?

• Lutein

• Carotene

• Curcumin

• Chlorophyll

Why does curcumin not dissolve well in water?

• Because water is a non-polar solvent

• Because curcumin is a polar compound

• Because water is a polar solvent

• Because curcumin is a charged molecule

What happens to curcumin when a base is added to its water suspension?

• It remains unchanged

• It becomes positively charged

• It loses protons and becomes negatively charged

• It forms a precipitate

What color does curcumin emit under ultraviolet light when dissolved in acetone?

• Orange

• Yellow-green

• Blue

• Red

At which pH level does curcumin lose its fluorescence?

• pH 9

• pH 7

• pH 4

• pH 8

What is observed when curcumin is exposed to a very high pH?

• It becomes colorless

• It emits a red glow

• It regains some orange fluorescence

• It turns blue

What property of curcumin is explored by using buffers of different pH levels?

• Its color change

• Its solubility

• Its reactivity with borates

• Its fluorescence

What complex is formed when curcumin reacts with borates?

• Roseosignin

• Carotene

• Lutein

• Chlorophyll

What indicates the presence of roseosignin in the reaction with borates?

• A yellow-colored mixture

• A red-colored mixture

• A green-colored mixture

• A blue-colored mixture

What is the role of sodium tetraborate in the reaction with curcumin?

• It oxidizes curcumin

• It forms a complex with curcumin

• It neutralizes curcumin

• It acts as a solvent