Red cabbage Indicator

Acids and bases

It contains pigment molecules known as flavin. This water-soluble pigment can be found in plums, apple skin and grapes. Hence, the pH of a solution can be determined based on the color it turns in the red cabbage juice.

Aim

To determine which chemicals are bases and which are acids.

An acid is a chemical compound that dissolves in water and turns into a solution whose activity of hydrogen ion is higher than pure water(pH < 7.0). Robert Boyle defined properties of acids as being corrosive to materials, sour taste and less acidic when mixed with bases.

A base is a chemical completely opposite of an acid. Neutralization takes place when a base is added to an acid. Bases decrease the concentration of hydronium ion in water. They become less basic when mixed with acids.

Apparatus Required

  • Water
  • Red cabbage leaves
  • Colanders
  • Vinegar
  • Lemon juice
  • Soda(baking soda)
  • Detergent
  • Glass jars of the similar size

Procedure

  • Cut the cabbage leaves into pieces.
  • Boil separate cups of water as they will be required to submerge your pieces later on.
  • Place the cabbage pieces in a bowl and pour the water in the bowl. Keep it for thirty minutes so that the cabbage pieces get soaked.
  • Separate the juice from the leaves.
  • Line up the glass jars about two inches apart. Pour every chemical(lemon juice, vinegar, detergent and soda) in each jar.
  • Now test whether the chemical is a base or an acid. Pour a half of your cabbage into each jar. You may have to swirl your mixture a bit. If the mixture turns pink, the chemical is an acid and if it turns blue, the chemical is a base.

This experiment can be conducted in your kitchen with easily available items. Moreover, it is recommended to soak cabbage for minimum least thirty minutes but stretching it for an hour can be more effective.

Conclusion

Chemicals are either bases or acids. When the cabbage was left in the boiling water, the cabbage juice was extracted, and that serves as an acid or base indicator, or detector. When it is added to different chemicals, the color change shows which chemical is a base and which is an acid.

Learn more about Acid properties and Base properties and their different uses with video lectures only @Byju’s


Practise This Question

Observe the pattern given below

 

 

Then term at nth position will be given by expression