Discover STEM - What is Hibiscus?

Is it true that Hibiscus, Malaysia’s National Flower,

can be used to indicate the acidity or alkalinity of substances?

Hibiscus had been declared as the national flower for Malaysia in 1960.

The red petals symbolise courage, and the five petals represent the Rukun Negara (National Priniciples).

Let us look into the flower parts in detail..

Commonly used pH indicators are synthetic, however, a hibiscus flower can be used to make a natural indicator.

Which part of the hibiscus flower do you think can be used?

It’s the petals!

Let’s explore this simple experiment on how to produce natural indicator from Hibiscus rosa-sinensis colour extraction.

How do we do it?

Step 1

Remove the stigma, and detach the leaves, to have only the red petals remaining.

Step 2

Put them in a container and pour approximately 6ml of ethanol or surgical spirit; the latter works best.

Step 3

Crush the petals using a mortar and pestle until most of the liquid has been extracted from the petals.

Step 4

Filter the solution, and you have the purple reddish indicator ready!

What will happen?

Here are the results after we mixed the indicator with different substances.

What actually happened?

Various shades of colours

There are various colours of Hibiscus rosa sinensis flowers. The various shades exhibited by the flowers are due to a very small number of different pigments (anthocyanin).


Antocynanins are coloured water-soluble pigments that are responsible for the colours in plants.

Neutral Solution

The acid salts of these pigments are usually red, their metallic salts usually blue and in neutral solution anthocyanins are violet.

Because of these characteristic, Hibiscus rosa sinensis can be used as an acid-base pH indicator.

What is a pH Indicator?

Example of Hibiscus extracts as an indicator at different PH.

A pH indicator or acid-base indicator is a compound that changes colour in solution over a narrow range of pH values.

The pH values of a neutral solution is 7.0. Solutions with a pH value below 7.0 are considered acidic and solutions with pH value above 7.0 are base (alkaline).

Other examples of natural indicators are turmeric, red cabbage, china rosa and grape juice.

What are the advantages of natural indicator compared to synthetic indicator?

Natural Indicator

  • Much cheaper
  • Less toxic to users
  • Environmentally friendly

Synthetic Indicator

  • High cost
  • Have toxic effects on users such as diarrhea, pulmonary edema, hypglycemia etc.
  • Can cause environmental pollution

Can the use of naturally-deprived compounds from hibiscus help save the environment?

As hibiscus flower contains the colour pigment anthocynanin, not only can it be used as a natural indicator, it can also be used to produce natural dye that is eco-friendly and safe on human skin.

Synthetic textile dye has been known to be toxic and carcinogenic, and as the efflents from the dyeing process enters water bodies, it pollutes the environment and cross the food chains.

Due to the harmful effects of synthetic dye to the environment, there a growing awareness and demand on the production of natural dye. As Malaysia is a biodiversity hotspot, other than hibiscus, there are a myriad of plants can potentially be researched as an alternative to the synthetic dyes.

0 Bandarqq pkv BandarQQ PKV Games Poker QQ Bonus New Member
slot gacor pkv games pkv games slot77 judi bola pkv games bandarqq robopragma slot gacor thailand slot thailand slot gacor gb777 bonus new member pkv slot77 slot hoki bonus new member mpo play slot bri slot bca slot dana slot mahjong ways slot77 slot123 bandarqq dominoqq slot triofus slot thailand pkv games bandarqq dominoqq pkv games slot triofus bandarqq bandarqq bandarqq dominoqq dominoqq pkv games pkv games pkv games pokerqq slot77 slot77 slot123 slot123 pkv games pkv games pkv games pkv games pkv games bandarqq dominoqq dominoqq dominoqq dominoqq dominoqq MPO mpo play mpo play bandarqq pkv games domino99 dominoqq bandarqq bandarqq pkv games pkv games pkv games jam hoki main slot jam hoki main slot bandarqq bandarqq
slot gacor slot777
pkv games pkv qq slot pulsa 5000 bandarqq pkv games bandarqq judi qq slot88 slot gacor toto slot slot gacor pkv games poker pulsa Situs Toto mpo slot mpo slot slot pulsa bandarqq qq online pkv games slot gacor pkv games dominoqq dominoqq pkv games pkv games pkv games akun pro kamboja slot zeus pkv games situs pkv games judi bola pkv dominoqq bandarqq slot hoki pg slot pkv games situs toto toto slot live draw hk idnslot live draw dominoqq pkv depo 25 bonus 25 bandarqq idn poker pkv slot pulsa judi bola slot77 pkv games slot thailand rtp slot rtp slot bandarqq slot server kamboja Live Draw SGP slot demo pg soft depo 25 bonus 25 depo 25 bonus 25 dominoqq slot gacor slot88 sbobet slot server thailand slot gacor dominoqq bandarqq slot gacor slot777 pkv games dominoqq slot hoki slot server thailand slot77 slot88 judi bola slot kamboja pkv mpo slot slot kamboja slot gacor slot pulsa slot ovo bocoran admin jarwo depo 25 bonus 25 bocoran admin jarwo dominoqq slot demo idn slot slot777 pkv games idn slot rtp live slot gacor slot77 slot dana idn slot pkv games akun pro malaysia depo 25 bonus 25 mpo slot depo 25 bonus 25 depo 25 bonus 25 pkv games deposit pulsa tanpa potongan slot4d akun pro kamboja slot777 idn slot depo 25bonus 25 slot77 slot gacor hari ini pkv games bandarqq bandarqq rtp live rtp bet pkv pkv pkv games rtp bet slot thailand slot777 slot server thailand slot777 rtpbet bocoran admin jarwo slot hoki judi parlay rtp live Pkv slot gacor slot pulsa idn poker bandarqq slot gacor Slot Demo Pg Soft Slot Demo dominoqq pkv pkv games slot gacor slot gacor slot pulsa slot dana judi slot triofus
sbobet casino online slot online
rtp bet pkv games rtp bet Judi Bola Dominoqq rtp bet akun pro kamboja idn poker dominoqq pkv games slot gacor depo 25 bonus 25 slot gacor Judi Bola Indonesia Vs Argentina Judi Bola Indonesia Vs Argentina slot server kamboja situs toto
live draw sgp slot pulsa toto macau idn slot slot gacor slot888 slot dana slot thailand Toto88 Slot Pulsa Toto88 Toto88 Sbobet88 Situs Toto Slot4d Slot777 Slot777 Slot Gacor