1.1.3 - Acids

Question 0

State the formula of hydrochloric acid.

Answer 0

HCl

Question 1

When an acid is added to water, what does it release in the aqueous solution?

Answer 1

The acid releases H+ ions (protons) into the solution.

Question 2

State the formula for sulfuric acid.

Answer 2

H₂SO₄

Question 3

What is the formula for nitric acid?

Answer 3

HNO₃

Question 4

State the formula of sodium hydroxide.

Answer 4

NaOH

Question 5

State the formula of potassium hydroxide.

Answer 5

KOH

Question 6

What is the formula for ammonia?

Answer 6

NH3

Question 7

What is the definition of a ‘base’? Give 2 examples of some common bases.

Answer 7

A base - A species that is a proton acceptor. It is the opposite of an acid. E.g:

• Common bases are metal oxides, metal hydroxides and ammonia.
• MgO, CuO, NaOH, Mg(OH)₂, NH₃.

Question 8

True or false: An alkali is any chemical compound that gives a solution with a pH greater than 7.0 when dissolved in water.

Answer 8

True - Alkalis have a pH greater than 7.0

Question 9

True or false: an alkali is an insoluble base that releases OH- ions in aqueous solution?

Answer 9

False - An alkali is a soluble base. True - However it does release OH- ions in aqueous solution.

Question 10

What is the difference between a ‘base’ and an ‘alkali’?

Answer 10

A base is a species that is a proton acceptor. An alkali is a special type of base that dissolves in water forming aqueous hydroxide (OH-) ions.

Question 11

When a salt is produced, explain what happens to the H+ ion of the acid.

Answer 11

The H+ ion is replaced by the metal ion or NH₄+.

Question 12

Sulfuric acid has two replaceable H+ ions (a diprotic acid). When forming a salt, one H+ ion is replaced by the metal ion. What happens to the other H+ ion and what type of salt has been formed?

Answer 12

The other H+ ion remains making the salt into an acid salt.

Question 13

Describe the reaction and its products between an acid and a carbonate.

Answer 13

Acid + Carbonate —> Salt + CO₂ + H₂O

Because CO2 is being produced, you will see bubbles during this reaction.

Question 14

Describe the reaction and its products between an acid and a base.

Answer 14

Acid + Base —> Salt + H₂O

Question 15

Describe the reaction and its products between an acid and an alkali.

Answer 15

Acid + Alkali —> Salt + Water

Question 16

Salts can be produced by neutralising acids with what 3 things?

Answer 16

• Carbonates
• Bases
• Alkalis.

Question 17

Salts can also be formed from the reaction of reactive metals with acids. What are these reactions known as?

Answer 17

Redox reactions.

Question 18

Explain the term ‘water of crystallisation’.

Answer 18

Water of crystallisation - refers to the water molecules that form an essential part of the crystalline structure of a compound.

Question 19

Explain the term ‘anhydrous’.

Answer 19

Anhydrous - refers to the substance that contain no water molecules.

Question 20

Explain the term ‘hydrated’.

Answer 20

Hydrated - refers to a crystalline compound containing water molecules.