Acids & Bases Characteristics Examples solution with pH < 7 tastes sour react with bases turn litmus red solution with pH > 7 tastes bitter soapy texture (slippery feel) react with acids turn litmus blue Strong: stomach acid battery acid strong hydrochloric acid Weak: tomato juice saliva coffee ammonia drain cleaner oven cleaner baking soda detergent antacids Characteristics Examples

pH measure of hydrogen ions in a solution pH < 7 pH = 7 pH > 7 acidic neutral basic (or alkaline) 4.6 – Fish Start to Die 4.0 – Most Animals Dead Lakes & Soil in Alberta ACIDIC NEUTRAL BASIC Oven Cleaner Stomach Acid Tomato Juice Pure Water Human Blood Antacids

Wine Carrots Acid Rain Aspirin Rain Water Milk Human Blood Borax Toothpaste Detergent/Soap Household cleaners Sodium hydroxide (NaOH)

Measuring pH pH meter acid-base indicators universal indicators directly measure pH acid-base indicators e.g. blue litmus paper turns red in acid e.g. pink litmus paper turns blue in base universal indicators e.g. phenophthalein, bromothymol blue, methyl orange

Neutral Substances pH 7, neither acidic nor basic when an acid and base are mixed they react and form a neutral solution → this reaction is called NEUTRALIZATION neutralization produces salt and water e.g. HCl(aq) + NaOH(aq) → NaCl(s) + H2O(l) hydrochloric sodium sodium water acid hydroxide chloride

Impacts to the Environment industrial activities emit gases such as CO2 and SO2 when these gases dissolve in water they form acids → ACID RAIN acid rain can lower the pH of water and soil… having a negative impact on the health and survival of many living organsims sometimes we treat acidic areas with lime (a base) to neutralize the acid