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What happens when Acids react with water?

• When hydrochloric acid is added to water to make a solution, it reacts with the water molecules.
• The hydrochloric acid will dissociate into 𝐻⁺ 𝑎𝑛𝑑 𝐶𝑙⁻ ions but this happens only in aqueous solutions. The reaction is

𝑯𝑪𝒍(𝒂𝒒) → 𝑯⁺ + 𝑪𝒍⁻

• The hydrogen ion reacts with water to give the hydronium ion because hydrogen ions cannot exist alone. They only exist after combining with the water molecule. This can be generalized as

𝑯⁺ + 𝑯𝟐𝑶 → 𝑯𝟑𝑶⁺𝒊𝒐𝒏

• There are two ways in which we can represent the hydrogen ions, 𝑯⁺(𝒂𝒒)𝑜𝑟𝑯𝟑𝑶⁺

Dissociation into 𝑯⁺𝒂𝒏𝒅𝑪𝒍⁻

Dissociation into 𝑯𝟑𝑶⁺

What happens when Bases react with water?

• Bases generate hydroxide ions in water, except dry bases. This can be generalized as

Base → 𝑶𝑯⁻in the presence of water

• When a base like potassium hydroxide is added to water, it will dissociate into 𝐾⁺ and

𝑂𝐻⁻ ions. The reaction is

KOH (s) (In presence of water) → 𝑲⁺(𝒂𝒒) + 𝑶𝑯⁻(𝒂𝒒)

• The OH^{-} ions exist by themselves and are responsible for the basic properties of a base.
• Sodium hydroxide is one more example of a base reacting with

NaOH (s) (In presence of water) → 𝑵𝒂⁺(𝒂𝒒) + 𝑶𝑯⁻(𝒂𝒒)

Dissociation into 𝑶𝑯⁻