Material Changes

What is the pH of a neutral solution?

• pH 7

• pH 11

• pH 4

• pH 1

A liquid has pH of 1. What type of liquid is it?

• Alkali

• Acid

• Neutral

What colour is universal indicator when the solution is neutral?

• Blue

• Red

• Green

• Orange

What sort of reaction happens when an acid and an alkali are mixed up?

• It becomes a strong acid

• It becomes a strong alkali

• It becomes a neutral solution

Where does the acid in your mouth comes from?

• From the air

• From water

• From the food we eat

Why is an alkaline substance dropped into lakes in some countries?

• So the lake is neutralized for animals

• So the lake becomes alkaline

What is the thing that farmers spread onto acidic soil?

• Baking Soda

• Bleach

• Lime

What is a fair test?

• A fair test is a test in which all variables are same except one.

• A fair test is a test in which all variables are same.

• A fair test is a test in which all variables are different.

“Litmus changes into red when it’s in an acid and changes to blue when it’s into a alkali, it is purple in a neutral solution.” What is the scientific term for a substance that changes colour in this way?

• Litmus paper

• Acid

• Indicator

What colour does litmus paper show in pure water?

• Green

• Red

• Blue

• Does not show any colour