Acid-Base Reactions

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Slide 1

Acids and Bases

Slide 2

Properties of Acids

Acids are proton (hydrogen ion, H+) donors

Acids have a pH lower than 7

Acids taste sour

Acids effect indicators

Blue litmus turns red

Methyl orange turns red

Acids react with active metals, producing H2

Acids react with carbonates

Acids neutralize bases

Slide 3

Acids are Proton (H+ ion) Donors

Strong acids are assumed to be 100% ionized in solution (good H+ donors).

Weak acids are usually less than 5% ionized in solution (poor H+ donors).

HCl

H2SO4

HNO3

H3PO4

HC2H3O2

Organic acids

Slide 4

Acids Have a pH less than 7

Slide 5

Acids Effect Indicators

Blue litmus paper turns red in contact with an acid.

Methyl orange turns red with addition of an acid

Slide 6

Acids React with Active Metals

Acids react with active metals to form salts and hydrogen gas.

Mg + 2HCl  MgCl2 + H2(g)

Zn + 2HCl  ZnCl2 + H2(g)

Mg + H2SO4  MgSO4 + H2(g)

Slide 7

Acids React with Carbonates

2HC2H3O2 + Na2CO3

2 NaC2H3O2 + H2O + CO2

Slide 8

Effects of Acid Rain on Marble (calcium carbonate)

George Washington:

BEFORE

George Washington:

AFTER

Slide 9

Acids Neutralize Bases

HCl + NaOH  NaCl + H2O

Neutralization reactions ALWAYS produce a salt and water.

H2SO4 + 2NaOH  Na2SO4 + 2H2O

2HNO3 + Mg(OH)2  Mg(NO3)2 + 2H2O

Slide 10

Properties of Bases

Bases are proton (hydrogen ion, H+) acceptors

Bases have a pH greater than 7

Bases taste bitter

Bases effect indicators

Red litmus turns blue

Phenolphthalein turns purple

Solutions of bases feel slippery

Bases neutralize acids

Slide 11

Bases are Proton (H+ ion) Acceptors

Sodium hydroxide (lye), NaOH

Potassium hydroxide, KOH

Magnesium hydroxide, Mg(OH)2

Calcium hydroxide (lime), Ca(OH)2

OH- (hydroxide) in base combines with H+ in acids to form water