Acid and Base Reactions

Types of Acid-Base Reactions

• Nuetralization reaction – properties of both acid and base are neutralized when they react

• Acid + Base Salt + Water– Salt – ionic compound (metal + nonmetal)

Strong Acid + Strong Base

• Strong acids completely ionize

• Strong bases completely ionize

• Ionic equation – everything (aq) written as ions– Spectator ions– Net ionic equation

• NaOH (aq) + HCl (aq) NaCl(aq) + H2O(l)

• H2SO4(aq) + 2KOH(aq) K2SO4(aq) + H2O(l)

• Strong acid + strong base & pH– Hydrogen ion from acid and hydroxide ion from

base form water which has a pH of 7

Strong Acid + Weak Base

• Weak bases do not completely ionize

• 3HBr(aq) + Al(OH)3(s) AlBr3(aq) + H2O(l)

Bronsted-Lowry Acids & Bases

• Acid – H+ donor• Base – H+ acceptor

• HC2H3O2 + NH3 NH4 + + C2H3O2-

• Conjugate base – formed when acid donates proton

• Conjugate acid – formed when base accepts a proton

• HC2H3O2 + NH3 NH4 + + C2H3O2-

• Identify the acid, base, conjugate acid, and conjugate base in the following:

• HCO3 -1 + H2O CO3 -2 + H3O +1

Strong Acid + Ammonia

• HCl(aq) + NH3(aq) NH4Cl(aq)

Weak Acid & Strong Base

• HC2H3O2(aq) + NaOH NaC2H3O2 + H2O

Applications of Acid-Base Reactions

• Buffers regulate pH– Solution that resist changes in pH when moderate

amounts of acids or bases are added– Prepared by using a weak acid and its conjugate

base or weak base and its salt

Acid-Base Chemistry & Antacids

• pH of stomach acid = 2.5• Stomach is coated with basic mucous to

protect it • If stomach becomes too acidic mucous layer

breaks down by acid-base neutralization• Antacids are bases

Acid-Base Titrations

• Titration – process of determining molarity of an acid or a base through the use of an acid-base reaction– Molarity of one of the reactants is known but the

other is unknown– Standard solution – solution whose molarity is

known

• Standard solution is loaded into a buret– Allows an accurate measurement of the delivery

of a given volume of liquid

• Using indicators – when solution is neutral you know you have added exactly enough stock solution to react with the unknown solution– endpoint

• A 15.0 mL sample of a solution of H2SO4 with unknown molarity is titrated with 32.4 mL of 0.145 M NaOH to the endpoint. What is the molarity of the sulfuric acid solution?