Acids, Bases and the pH ScaleGrade 9 and 10 ScienceMr.MacMillan

Acids• Compounds that produce hydrogen

ions, H+, when dissolved in water.

• HCL H+ + Cl-• Hydrochloric acid is formed when

hydrogen chloride gas is added to water.

Naming Acids

• Binary Acids– Composed of hydrogen and a non-

metal

• HF – hydrofluoric acid• HBr – hydrobromic acid• HI – hydroiodic acid

• Oxoacids– Composed of hydrogen, oxygen and

another element

• H2 SO4 – sulfuric acid• HNO3 - nitric acid• H3 PO4 – phosphoric acid• H2 CO3 – carbonic acid

Bases

• Compounds that form hydroxide ions, OH- , when dissolved in water

• NaOH Na+ + OH-

Naming Bases

• NaOH – Sodium hydroxide• Mg(OH)2 – Magnesium hydroxide• Ca(OH)2 - Calcium hydroxide

The pH Scale

• pH Taste Test

Litmus Paper

• A pH indicator that changes colour to show the concentration of hydrogen ions and hydroxide ions in a solution

• Blue litmus paper turns red in an acidic solution• Red litmus paper turns blue in a basic solution• Neutral – no colour change