2. Bases

Question 1

What are bases?

Answer 1

Bases are substances which can neutralise an acid, forming a salt and water.

Question 2

Bases are usually … of metals

Answer 2

Oxides, hydroxides or carbonates of metals

The presence of the OH- ions is what makes the aqueous solution an alkali

Question 3

What is an alkali

Answer 3

A base which is water-soluble is referred to as an alkali.

So, all alkalis are bases, but not all bases are alkalis

Question 4

Sodium hydroxide

Formula and Ions formed in water

Answer 4

NaOH

Na+, OH-

Question 5

Potassium hydroxide

Formula and Ions formed in water

Answer 5

KOH
K+, OH-

Question 6

Aqueous ammonia/ ammonium hydroxide

Formula and Ions formed in water

Answer 6

NH3 (+ H2O)
NH4+, OH-

Aqueous ammonia = ammonium hydroxide. Ammonia (NH₃) is the gas; ammonium (NH₄⁺) is the ion in compounds.