Slippery, bitter... and a trap
Bases feel slippery and taste bitter, but bitter alone does not prove a base.
Two clues
Soap feels slippery in your hands. Bitter gourd (karela) tastes bitter.
Which of these do you think is basic?
What this lesson covers
The idea
Basic substances are generally slippery to touch and bitter in taste, but not everything that tastes bitter contains a base.
Two clues
Soap feels slippery in your hands. Bitter gourd (karela) tastes bitter.
Which of these do you think is basic?
- Only soap, because it is slippery
- Only karela, because it is bitter
- Both of them
Guess, then check
For each liquid, read the clue, guess if it is a base, then check with red litmus. A base turns red litmus blue.
Clues are not proof
Soap solution and washing powder solution turned red litmus blue. Karela juice did not.
Basic substances are generally slippery to touch and bitter in taste, but not everything that tastes bitter contains a base.
So slippery and bitter are clues. The litmus test is the proof. Keep safe: never touch or taste an unknown liquid, because strong bases can harm the skin.
Notes
Basic substances are generally slippery to touch and bitter in taste, but not everything that tastes bitter contains a base.
Check yourself
A liquid turns red litmus blue and feels slippery. It is...
Karela juice tastes bitter, but red litmus stays red. What does this show?
Which pair describes bases best?
What is the most trustworthy way to be sure a liquid is a base?
- acidic. Acids turn blue litmus red and do not feel slippery.
- basic — correct. Yes! Red litmus turning blue shows a base, and slippery fits.
- neutral. A neutral liquid changes neither strip.
- Karela juice is basic. A base would turn red litmus blue.
- Karela tastes bitter, but it is not basic — correct. Yes! Bitter taste alone does not prove a base.
- The litmus paper is spoilt. The litmus is fine. Not everything bitter is a base.
- Sour and slippery. Sour is the clue for acids.
- Slippery and bitter — correct. Yes! Bases are generally slippery and bitter.
- Sour and bitter. Sour is the clue for acids, not bases.
- Taste it. Never taste unknown liquids. And bitter alone is not proof.
- Dip red litmus: it turns blue — correct. Yes! The litmus test is the proof.
- Touch it and see if it is slippery. Slippery is only a clue, and touching unknown liquids is unsafe.