Neutralisation (Please copy these main points to your books)                                                    (Please copy these main points to your books) (And ensure that you read page 59-60)

pH The CONCENTRATION of hydrogen ions …wether an acid is weak or strong or if a substance is a base or not is measured on the pH scale In an acid there are more hydrogen ions than Hydroxide In a base there are more hydroxide than hydrogen ions Pure water is neither- its neutral pH 7- has = numbers of both types of ions

Ph SCALE You have one to colour on page 6 of your booklet USE PAGE 59 TO HELP…OR

Indicators These are chemicals that change colour to show whether a substance is an acid or a base Common indicators: Litmus paper Universal indicators PH meters It is important to monitor pH especially in pools – look at page 17 of your booklet/pg 60 of the text Red cabbage indicator practical

*A base can neutralise an acid pg 78 It removes the H+ ions and converts them to water. For example: Sodium hydroxide + Hydrochloric Acid -> Sodium Chloride + Water (base) (acid) Na+Cl- + H2O Sodium Chloride is commonly called what?

Points to Remember! Any substance that can neutralise an acid is called a base. Neutralisation always produces a salt. There are neutralisation reactions which occur everyday: *Insect Stings *Soil treatment *Indigestion *Factory waste