Class 7 Science Ch- Acids,Bases and Salt

What is the chemical nature of acids ?

• Acid

• Basic

• Acidic

• None of the above

What is the chemical nature of bases ?

• Bases

• Basic

• Acidic

• None of the above

Substances which are bitter in taste and feel soapy in texture are known as

• Bases

• Acid

Special type of substances are used to test whether a substance is acidic or basic. These substances are known as

• Indicators

• Gudhal

• None of the above

Identify the image.

• Fungus

• Lichens

• Plant

Acids turn ____________ and Bases turn_____________.

• Both turn red litmus blue

• Blue litmus red, Red litmus blue

• Both turn blue litmus red

• No change

An acid and a base neutralise each other and form __________

• Remains the same

• Chemical substance

• Salt

• None of the above

Tooth decay is formed by the presence of base.

• True

• False

Change in colour in an acid and a base depends on the type of indicator.

• True

• False

If an indicator gives changes colour with a acid it does not change colour with an acid.

• True

• False