Neutral Is At Ion

Neutralisation LO: • Observe what happens when an acid is added to an alkali. • Use indicators to monitor neutralisation reactions.

Adding an acid to an alkali What do you think will happen to the colour of the indicator if we slowly add an acid to the alkali. Write a prediction in your book.

Method 1. 2. 3. 4.

Put 2 ml of ammonia in your conical flask. Add a few drops of universal indicator. Put 10 ml of ethanoic acid in a beaker. Use a pipette to add 5 drops of acid to the conical flask. 5. Swirl the liquid in the conical flask. 6. Note the change of colour and pH number in your results table. 7. Repeat steps 4 – 6.

Ammonia

Conical Flask

Ethanoic Acid

Beaker

Universal Indicator

Pipette

The pH scale stronger alkali

stronger acid

1 2 3 4 5 6 7 8 9 10 11 12 13 14 Strong acid

Weak acid

neutral

Weak alkali

Strong alkali

Results

The pH of the liquid in the test tube went down. When we add an acid to an alkali the pH changes. We call this change a chemical

reaction.

Acid + Alkali  Neutral

Neutralisation When the pH in our test tubes reaches 7, we say NEUTRALISATION has happened. Neutralisation can be very useful in some situations…