tests for acids, bases and water

Question 1

Acids

Answer 1

• universal indicator - green indicator turns red
• blue litmus paper turns red

Question 2

Alkalis (bases)

Answer 2

Soluble hydroxides:
- universal indicator - green indicator turns blue/purple
- red litmus paper turns blue
- no visible reaction with dilute acid

Soluble carbonates:
- same as above
- produces CO₂ gas in reaction to dilute acid

Question 3

Water

Answer 3

• cobalt chloride paper - blue paper turns pink
• anhydrous copper sulphate - white powder turns blue