Chapter 19: Acids and Bases

Acid

A compound that produces H+ ions when dissolved in water

Acid examples

Vinegar (acetic acid), lemon juice (citric acid), tea (tannic acid), ant venom (formic acid)

Properties of acid

• Sour taste

• corrosive

• turns litmus paper red

• reacts with metals to form H2 hydrogen gas

• Aqueous solutions of acids are electrolytes (must be mixed with water)

• Reacts with bases to form H2O and salt

Strong acids

Completely ionize in water

3 binary acids

HCl, HBr, HI

Ternary acids

Strong if # of 0 atoms - # of H atoms >= 2

Weak Acids

Ionize only slightly in aqueous solutions

Binary acids

All others that aren’t HCl, HBr, HI

Ternary Acids

Weak if # of 0 atoms - # of H atoms >= 1

Base

A compound that produces OH- ions (hydroxide) when dissolved in water

Base examples

Milk of Magnesia (magnesium hydroxide), Drain cleaner (sodium hydroxide)

Properties of Bases

• Bitter

• Slippery

• Turns litmus paper blue

• Aqueous solutions of bases are electrolytes (must be mixed with water)

  • Reacts with acids to form H2O and salt

Strong Bases

• Completely ionize in water (create a lot of OH- ions)

• All hydroxides with groups 1 and 2 metals (except Be)

Weak Bases

Ionize only slightly, all bases not listed before as strong

Arrhenius Theory (Acid)

Must contain a H and ionize in water to produce H+/H3O+

Ex. HCl + H2O → H3O+ + Cl

Arrhenius Theory (Base)

Must contain an OH and dissociates in water to produce OH-

Ex. NaOH → Na+ + OH-

Disadvantages of Arrhenius Theory

• Only compounds with OH- can be classified as a base

• Can only be applied to reactions that occur in water

  • Would incorrectly classify some compounds as acids, such as CH4

Ca(OH)2 Acid or Base?

Base

HBr Acid or Base?

Acid

H2SO4 Acid or Base?

Acid

LiOH Acid or Base?

Base

Brosnted-Lowry Theory (Acid)

Any substance that can donate a H+

Bronsted Lowry Theory (Base)

Any substance that can accept H+

Bronsted Lowry Theory (Conjugate Acid)

Formed when a base accepts a H+ from an acid

Bronsted Lowry Theory (Conjugate Base)

A particle that remains after an acid gives up a H+

Acidic range

Less than 7

Base range

More than 7

What happens when you mix an acid with a base?

A double replacement reaction

Neutralization Reaction

• Products are always a salt (nonmetal and metal) and water

  • acid + Base → salt + water

Titration

A process in which an acid-base neutralization is used to determine the concentration of a solution

• M(V)/mol = M(V)/mol

Buffer

A solution that resists changes in pH when limited amounts of acids or bases are added

Buffer capacity

The amount of acid or base a buffer can absorb before its pH changes significantly

Acid, Base or Salt? Mg(OH)2

Base

Acid, Base or Salt? Magnesium sulfate

Salt

Acid, Base or Salt? Lithium hydroxide

Base

Acid, Base or Salt? HNO3

Acid

Acid, Base or Salt? Hydroiodic

Acid

Acid, Base or Salt? H3PO4

Acid

Acid, Base or Salt? CaCl2

Salt

Acid, Base or Salt? KOH

Base

Strong Acids

HCl, HBr, HI, H2SO4, HClO4

Strong acids are in which column?

1 and 2

Indicators

Substances that change color depending on the pH of a solution and are used to determine whether a solution is acidic or basic

Indicators examples

Litmus paper, phenolphthalein, bromothymol blue

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