Acids & Bases

Acids An acid is any substance that releases hydrogen (H+) ions in solution. Example: Nitric Acid HNO (aq)  H+ + NO -

Bases A base is any substance which releases hydroxide (OH-) ions in solution. Example: NaOH NaOH (aq)  Na+ + OH-

Acid/Base Strength Strength depends on % ionization. Examples: Sulphuric Acid – 100% of acid molecules ionize in solution = strong acid Acetic Acid – 0.5% of acid molecules ionize in solution = weak acid

pH Scale pH is a number scale that indicates the degree of acidity or basicity of a substance

Acid Properties Taste sour Reacts with metal to produce H+ Conduct electricity Neutralize bases Turn blue litmus paper red Common in fruits

Properties of Bases Taste bitter Feel slippery Conduct electricity Neutralize acids Turn red litmus paper blue Common in cleaners

Indicators An indicator is a chemical whose colour depends upon the degree of acid or base present Examples: litmus phenolphalein

Neutralization Neutralization is the reaction between an acid and a base. The products are a salt and water Example: HCl + NaOH  NaCl + H O Hydrochloric Sodium Salt Water Acid Hydroxide

Naming Acids Binary Acids: The prefix “hydro” is used followed by the other element, ending in “ic” Examples: HCl hydrogen chloride hydrochloric acid H S hydrogen sulphide hydrosulphuric acid HBr hydrogen bromide hydrobromic acid

Naming Acids Tertiary Acids (H+ bonded to polyatomic ion) If the name of the anion ends in “ate”, the name of the acid ends in “ic” Example: H PO hydrogen phosphate phosphoric acid If the name of the anion ends in “ite”, the name of the acid ends in “ous” HNO hydrogen nitrite nitrous acid

Naming Acids Prefixes “per” and “hypo” Examples: HClO hydrogen hypochlorous hypochlorite acid HClO hydrogen perchloric perchlorate acid

Naming Bases With the exception of ammonia, just add “hydroxide” to the name of the element in question. Examples: NaOH sodium hydroxide KOH potassium hydroxide Mg(OH) magnesium hydroxide