Ch ChemAI

All experiments › First chemistry (grades 7–8)

Acid meets base

Add acid to a base until the pink colour disappears: neutralisation.

Topic: First chemistry (grades 7–8)Grade: 8Free

🧪 Start the experiment — free

Runs in the browser on phones, tablets and computers. No sign-up needed. For teachers: assign any experiment to a class, see results and calculations.

What you do

  1. Add a few drops of phenolphthalein: the base turns pink.
  2. Add hydrochloric acid little by little until the pink just disappears.
  3. Turn on the pH meter: the solution is now close to neutral (pH 7). Acid + base → salt + water.

More experiments on this topic

Heating water: when does it boil?Watch the thermometer while water turns into steam — a change of state.Which ones dissolve in water?Salt, marble and an oil-like liquid: solution, sediment or two layers?Particles on the moveOne tiny purple crystal colours a whole beaker: the particles spread out by themselves.Cold packs and hot packsSome substances make water colder when they dissolve, others make it warmer.Kitchen indicator: red cabbageRed-cabbage juice changes colour in acids and in bases.Fizz! Which gas is it?Marble and acid make a gas. The limewater test tells you it is carbon dioxide.