Acids and alkali: Unit review

What colour is the strongest acid in the diagram?

What number is the lightest alkali in the chart?

What does it mean to neutralise a substance?

• destroy the substance

• make it taste nice

• cancel its properties

• make it have a neutral smell

Another name of alkali is:

Litmus is a dye made from a living organism.

It is red in an acid.

It is blue in an alkali.

It is purple in a neutral solution.

a. What is the correct scientific term for a substance that changes colour in this way?

Answer explanation

b. What colour is litmus in a solution of pH 4?

c. What colour is litmus in pure water?

Each of the following words and phrases are associated with acids or with alkali.

a. makes Universal indicator turn blue

b. makes Universal indicator turn red

c. pH 2

d. pH 9

e. soapy

f. sour

g. lemon juice

h. tooth paste

Below, choose the letters of the correct words/phrases associated with acids.

• b, d, f, g

• a, b, c, d

• b, c, f, g

• a, c, d, e

Each of the following words and phrases are associated with acids or with alkali.

a. makes Universal indicator turn blue

b. makes Universal indicator turn red

c. pH 2

d. pH 9

e. soapy

f. sour

g. lemon juice

h. tooth paste

Below, choose the letters of the correct words/phrases associated with alkali.

• a, d, e, h

• a, b, c, d

• b, c, f, h

• a, b, f, g

This truck is unloading acid at a factory.

The driver has placed a warning notice nearby.

a. Explain why this is important.

b. Suggest what could be done if there is an accident and some acid is spilt onto the ground . Explain your answer.