Acids and Bases

What are Acids?What are Acids? Acids are commonAcids are common Some are Some are

dangerous and dangerous and can burn your skincan burn your skin

Some are safe to Some are safe to eat and drinkeat and drink

Stomach acid Stomach acid helps digest foodhelps digest food

explosion

AcidsAcids

Definition Definition • All have low pH (0-6)All have low pH (0-6)• Turn Litmus paper REDTurn Litmus paper RED• Taste Sour, Corrosive,Taste Sour, Corrosive,

ExamplesExamples• Hydrochloric HClHydrochloric HCl

• Sulfuric HSulfuric H22SOSO44

• Nitric HNONitric HNO33

What are Bases (Alkalis)?What are Bases (Alkalis)?

In our home we In our home we often use bases often use bases to clean things. to clean things. Eg Bleach and Eg Bleach and toothpastetoothpaste

BasesBases

DefinitionDefinition• Have a high pH (8-14)Have a high pH (8-14)• Turn litmus BLUETurn litmus BLUE

ExamplesExamples• Ammonia NHAmmonia NH33

• Sodium Hydroxide NaOHSodium Hydroxide NaOH• BleachBleach• SoapSoap

Neutral

Water is considered Neutral It is neither an acid or base It has a pH of 7

Measuring acid strength?Measuring acid strength?

To decide if something is an acid or a To decide if something is an acid or a base we can use an indicator.base we can use an indicator.

Litmus and Universal Indicator are Litmus and Universal Indicator are examples of indicators.examples of indicators.

They change color depending on if They change color depending on if they are in an acid or a base.they are in an acid or a base.

Working with IndicatorsWorking with Indicators

Red litmus turns BLUE in the Red litmus turns BLUE in the

presence of Bases (alkali)presence of Bases (alkali) Blue litmus turns RED in the Blue litmus turns RED in the

presence of acidpresence of acid Acids and bases react together in Acids and bases react together in

a NEUTRALISATION reactiona NEUTRALISATION reaction

Acid ReactionsAcid Reactions

Acid + Base Acid + Base Salt + Water Salt + Water

Acid + Metal Acid + Metal Salt + Hydrogen Salt + Hydrogen

Acid + Carbonate Acid + Carbonate Salt + Water + Carbon Dioxide Salt + Water + Carbon Dioxide

• Hydrochloric acids form CHLORIDE saltsHydrochloric acids form CHLORIDE salts• Nitric acid forms NITRATE saltsNitric acid forms NITRATE salts• Sulfuric acid forms SULFATE saltsSulfuric acid forms SULFATE salts

Acid RainAcid Rain

Consider Consider • Causes Causes

naturalnatural humanhuman

• Effects Effects buildingsbuildings floraflora faunafauna healthhealth

• Chemical equationsChemical equations• Prevention/SolutionPrevention/Solution