Acids and alkalis

Target 1. To know the names of some acids

and alkalis 2. To know how to test for an acid or an

alkali

Monday, May 1, 2023

Acids

Acids are ‘sour’ substances

Acids are found in fruit like lemons

Laboratory acids like hydrochloric acid or sulphuric acid are very dangerous (corrosive)

Alkalis

Alkalis are substances that are not acids but react with acids – and cancel each others properties out.

Strong alkalis like sodium hydroxide are dangerous (corrosive)

Telling acids and alkalis apart

To test for an acid or alkali we use an indicator

Example – litmus Acids make litmus

red Alkalis make litmus

blue

Testing substancesSubstance Colour Type

Rainbow experiment Set up this

experiment in a test tube.

Put a washing soda crystal in a test tube of water.

Add a little acid to top up the test tube.

Add a few drops of universal indicator solution

Questions – pages 150 and 151

Quiz

Substances that burn skin are called corrosive. True or false?

Acids and alkalis are really the same. True or false?

Acids taste sour. True or false?

Lemons contain alkali. True or false?

Acids are red in litmus. True or false?

Alkalis are not corrosive! True or false?

Answers

T F T

F T F