Lesson 6.8: pH and Color Change

Interactive
Proton Transfer in Water

Embed

• The hydrogen atom in the water molecule has one proton and an electron that it shares with the oxygen atom. A proton from a hydrogen atom can transfer to another water molecule, creating the ions H₃O⁺ and OH^-.
• A proton from the H₃O⁺ ion can be transferred to the OH^-, creating water molecules again.

Image
Water Molecules Trade Protons

• The hydrogen atom in the water molecule has one proton and an electron that it shares with the oxygen atom. A proton from a hydrogen atom can transfer to another water molecule, creating the ions H₃O⁺ and OH^-
• A proton from the H₃O⁺ ion can be transferred to the OH^-, creating water molecules again.

Interactive
Acids Donate Protons

Embed

• An acid added to water donates protons to the water molecules. This increases the concentration of H₃O⁺ ions. The H₃O⁺ ions donate protons to the indicator molecules which results in a color change.

Interactive
Bases Accept Protons

Embed

• A base added to water accepts protons from the water molecules. This increases the concentration of OH- ions. The H3O+ ions and the indicator molecules donate protons to the OH- ions. This decreases the concentration of H3O+ ions and results in a color change.