Lesson 6b: Neutralisation

What are bases?

substances that can neutralise acids to form water.

What is a neutralisation reaction?

When an acid reacts with a base and a salt and water is produced.

Acid + Alkali =

salt + water

Acid + Metal oxide =

salt + water

Salt + Metal carbonate =

Salt + water + carbon dioxide

What is a salt?

A substance where the hydrogen ion of an acid is replaced with a metal (or ammonium) ions.

List 2 examples of neutralisation

-Antacid tablets used to neutralise stomach acids

-Lime is used to reduce the acidity of soil and lakes

List 3 points that should be considered when making a soluble salt

-the reagents to use

-best method to quickly neutralise the acid

-technique(s) to collect the dry sample

List the 3 steps to prepare soluble salt if the base is insoluble

-add the insoluble base in excess to the acid till some is left unreacted

-filter the solution to remove the excess base

-evaporate the solution to give a dry sample of salt

How do you prepare a soluble salt is the base is soluble?

Titration would be carried out with universal indicator to determine the end point. The experiment can be repeated without the indicator and the salt can then be collected by evaporation.

What is precipitation?

Mixing two soluble salts to form two solutions which then mix to form an insoluble salt

Define solute

Substance being dissolved

Define solvent

the liquid that does the dissolving

Define solution

a mixture of solute and solvent

Define saturated

when the maximum solute has been dissolved in the solvent

What is a standard solution?

Solution of accurately known concentration

What is an accurate way to determine the concentration of an acid or alkali?

To use a titration

List 2 apparatus involved in titration

Pipette and burette

What is step 1 of titration method?

A pipette and a pipette filler are used to add a known volume of acid and alkali to a conical flask

What is step 2 of titration method?

A few drops of indicator are added to the flask

What is step 3 of titration method?

The start reading on the burette is recorded and the alkali or acid is slowly added to neutralise the solution in the flask

What is step 4 of titration method?

At the end point of the reaction the indicator permanently changes colour. The end reading on the burette can be recorded

What is step 5 of titration method?

The titration should be repeated until concordant ( between 0.2 cm3) are obtained