Chemical Changes Revision

In acids, universal indicator will turn....

• Red

• Orange

• Yellow

• Purple

• Blue

Answer explanation

In acids, universal indicator will turn red, orange or yellow.

In alkalis, universal indicator will turn....

• Red

• Orange

• Yellow

• Purple

• Blue

Answer explanation

In alkali, universal indicator will turn blue or purple.

Acids are substances with a pH....

Answer explanation

Acids are substances with a pH of less than 7.

Alkalis are substances with a pH...

Answer explanation

Alkalis are substances with a pH above 7.

Which of these are examples of acids:

• Lemon juice

• Baking Soda

• Soap

• Vinegar

Answer explanation

Vinegar and lemon juice are both examples of everyday acids.

Which of these are alkalis:

• Lemon juice

• Baking soda

• Soap

• Vinegar

Answer explanation

Baking soda and soap are both examples of alkalis.

An example of a neutral substance is.....

Answer explanation

Blood and pure water are examples of everyday neutral substances.

When an acid is diluted, the pH will....

Answer explanation

When an acid is diluted, the pH will increase towards 7.

When an alkali is diluted, the pH will......

Answer explanation

When an alkali is diluted, the pH will decrease towards 7.

What colour would pure water turn universal indicator?

• Red

• Orange

• Green

• Blue

Answer explanation

Pure water would turn universal indicator green as it is a neutral substance.