Ammonia's basic nature, shown three ways
One property, checked three times: ammonia solution is a base, and every indicator that responds to a base should say so. This activity pours the same ammonia solution into three flasks and runs it against pH paper, methyl orange and phenolphthalein in turn — blue, yellow and pink are three different colours reporting the identical fact, which is the point of running all three rather than trusting just one.
6 steps · Ammonia · Study of Compounds
What you will use
Apparatus
- pH paper test
- Methyl orange test
- Phenolphthalein test
Chemicals
- Ammonia Solution
- Methyl Orange
- Phenolphthalein
The steps
-
Pour ammonia solution into the first flask.
Colourless, same as it will be in all three flasks before the indicator goes in.
-
Dip the pH paper into it.
The pH paper turns blue — the standard sign of a base.
-
Pour ammonia solution into the second flask.
Colourless, the same starting point as the first flask.
-
Add a few drops of methyl orange.
The solution turns yellow — methyl orange in a base.
-
Pour ammonia solution into the third flask.
Colourless, the same starting point as the other two flasks.
-
Add a few drops of phenolphthalein.
The solution turns pink — phenolphthalein in a base.
What it shows
Three indicators, one answer: ammonia solution is a base. pH paper turns blue, methyl orange turns yellow and phenolphthalein turns pink — three different chemistries built to react to the same thing, which is why agreement across all three is stronger evidence than any one of them alone.