Neutralisation

Question 1

What is a base?

Answer 1

A base is a substance that reacts with an acid to form salt and water only. They are insoluble in water.

An alkali is soluble in water

Question 2

What is a neutralization reaction?

Answer 2

A neutralization reaction is a reaction between an acid and a base

Question 3

What happens in an acid-alkali neutralisation?

Answer 3

In acid-alkali neutralisation reactions, hydrogen ions from the acid react with hydroxide ions from the alkali. Here are the ions involved in the reaction of hydrochloric acid with sodium hydroxide solution:

H+(aq) + Cl-(aq) + Na+(aq) + OH-(aq) → Na+(aq) + Cl-(aq) + H2O(l)

Now remove the spectator ions, Cl-(aq) and Na+(aq). This leaves:

H+(aq) + OH-(aq) → H2O(l)

Question 4

How do you investigate neutralisation? (The change in ph)

Answer 4

Use a measuring cylinder to add dilute hydrochloric acid to a beaker.

Dip a clean glass rod into the contents of the beaker. Use it to transfer a drop of liquid to a piece of universal indicator paper on a white tile. Wait 30 seconds, then match the colour to a pH colour chart. Record the estimated pH.

Add a level spatula of calcium hydroxide powder to the beaker.

Stir thoroughly, then estimate and record the pH of the mixture (as in step 2).

Repeat steps 3 and 4 until there are no more changes in pH.