Acid & Bases 1

Question 1

What colour do acids turn red litmus paper?

Answer 1

Nothing, it remains red

Question 2

What colour do acids turn blue litmus paper?

Answer 2

Red

Question 3

What colur do bases turn red litmus paper?

Answer 3

Blue

Question 4

What colour do bases turn blue litmus paper?

Answer 4

Nothing. It remains blue

Question 5

What is an alkali?

Answer 5

A water soluble base.

Question 6

What is neturalisation

Answer 6

The reaction between an acid and a base, forming a salt.

Question 7

What are everday uses of neturalisation?

Answer 7

• Resolving heartburn(with a base)
• Treating bee stings (bee stings are acidic)
• Liming soil to increase its pH

Question 8

What ia an Arrhenius acid?

Answer 8

A substance which dissociates in aqueous solution forming hydrogen ions

Question 9

What is an Arrhenius base?

Answer 9

A substance that dissociates in water to form hydroxide ions

Question 10

According to the Arrenhius theory, what causes a solution to be acidic

Answer 10

H⁺ ions

Question 11

What causes the basic properties in bases, according to the Arrhenius thoery.

Answer 11

The OH^- ions

Question 12

What is the difference between a weak and strong bases, according to the Arrhenius theory.

Answer 12

• Strong acids and bases full dissociate in water in solution
• Weak acids and bases only slightly dissociate in solution

Question 13

Explain neutralisation, in terms of the Arrhenius theory.

Answer 13

• A strong acid fully dissociates in water, creating a H⁺ ion and an anion e.g H⁺ and Cl^- from HCL
• A strong base fully dissociates in water froming a OH^- ion and a cation e.g OH^- and Na+
• When the two solutions react, the H⁺ and the OH^- to form water
• However the cation and anion don’t react as they are more attracted to the water molecules than each other

Question 14

What evidence is there for Arrhenius theory

Answer 14

• The thoery explains why strong acids only conduct electricty when dissolved in water(pure acids have no ions)
• It also explains why weak acids in solution don’t conduct as well as strong acids in solution. (Weak acids only dissociate slightly in water and so have less ions than strong acids, which fully dissociate)
• It similarly explains why weak bases don’t conduct electricity as well as strong bases.
• Explains why acids ussualy need water to show their acidic properties.

Question 15

what are the limitatoins of the Arrhenius theory?

Answer 15

• It is limited to acid-base reactions in water
• When acids dissolve in water, H₃O⁺ is formed rather than the hydrogen ion
• Doesn’t explain how ceretain substances are amphoteric(can act as an acid with a base and a base with an acid)