Changes

: When a [[compound]] does [[dissolve]] in [[water]] to produce an [[acid]] not all of the [[Hydrogen Ion (Chemistry)|Hydrogen ion]]s will dissociate from the [[compound]]. The strength of an [[acid]], or its [[acidity]], is determined by how easily [[Hydrogen Ion (Chemistry)|Hydrogen ions]] are formed. The more easily [[Hydrogen Ion (Chemistry)|Hydrogen ions]] form, the stronger the [[acid]] (the higher the [[acidity]].

: For a [[pH]] decrease of 1 there needs to be 10 times the number of dissociated [[Hydrogen Ion (Chemistry)|Hydrogen ions]] per [[litre]]. This will be affected by the [[concentration]] of [[acid]] and the strength of the [[acid]] ([[acidity]]).