2.1.2 Red Rose as an Indicator

What is Red Rose Extract?

It is a natural indicator prepared from  petals .

Key Facts and Examples

• Red rose extract gives red colour in acidic solutions .

Example: Lemon juice with rose extract turns red

• Red rose extract gives green colour in basic solutions .

Example: Soap solution with rose extract turns green

• Other natural materials can also act as indicators .

Example: Beetroot, purple cabbage, turmeric, jamun, hibiscus flower

Activity 2.2: Preparing Red Rose Extract

What you need:

• Fallen petals of red roses
• Mortar and pestle
• Glass tumbler
• Hot water
• Lid
• Filter paper

What to do:

• Step 1: Collect some fallen petals of red roses
• Step 2: Crush the petals using a mortar and pestle
• Step 3: Place them in a glass tumbler
• Step 4: Pour some hot water into the glass tumbler to ensure that the crushed flower petals are completely immersed
• Step 5: Cover the glass tumbler with a lid
• Step 6: Wait for 5-10 minutes till the water becomes coloured, and filter it

Observations

What you see:

• Crushed petals release red pigment into hot water
• Coloured water forms after 5-10 minutes
• Filtrate is the required flower extract

Why this happens:

We have studied that natural substances contain pigments that change colour in different solutions . This is why red rose extract can act as an acid-base indicator.

• Hot water extracts colour pigments from rose petals
• Pigments react differently with acids and bases

🌟 Fascinating Fact: Hydrangea is a plant that grows in cooler climates in the Himalayan region and the North-eastern states. It gives flowers of different colours, depending on the nature of the soil. Acidic soil produces blue coloured flowers, whereas in basic soil, the flowers are pink or red.