Acids

1
Acids Bases
solution with pH lt 7 tastes sour react with bases turn litmus red solution with pH gt 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 Strong ammonia drain cleaner oven cleaner Weak baking soda detergent antacids
Characteristics
Examples
2
pHmeasure of hydrogen ions in a solution

• pH lt 7 pH 7 pH gt 7
• acidic neutral basic
• (or alkaline)

4.6 Fish Start to Die 4.0 Most Animals Dead
Lakes Soil in Alberta
ACIDIC
BASIC
NEUTRAL
Oven Cleaner
Tomato Juice
Stomach Acid
Pure Water Human Blood
Antacids
3
Wine
Carrots
Acid Rain
Aspirin
Rain Water
Milk
Human Blood
Borax
Toothpaste
Detergent/Soap
Household cleaners
Sodium hydroxide (NaOH)
4
(No Transcript)
5
Measuring pH

• pH meter
• 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

6
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

7
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