W15 Sour cherries
and an opponent of acids
Acids
are all substances that have a sour taste. In the previous
experiment you have learned that citric acid and ascorbic acid have
another property: They are corrosive. Corrosive substances may damage
your
eyes:
Do not forget to wear GOGGLES! Ask an adult to be with you.
* Take a 1-ml syringe,
cut off the tip of the needle. * Suck juice from a sour cherry into
it.
* Left: Transfer
micro drops from the syringe on a white
plastic surface: 1. One
on the right side of the arrow, one on its left side.
2. Place 2 drops of lime water beside
the left micro drop and 3.
two drops on the right micro drop.
4. Use a needle to mix the liquids on the right
side
Observation:
The colour turns from red to green. *
Right: Add 1 micro drop of vinegar (25 %) to the green solution.
Mix: The colour turns from green to red again when it
is mixed with a micro drop of vinegar.
Remember:
Lime water
is an opponent of acids. Lime water makes red cherry juice green.
Vinegar
is an opponent of lime water. Vinegar makes green juice red
again.
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modification: 12.09.2001