Acids and Bases

Arrhenius Acid & Base

Which beaker contains a base?

Bronsted Lowry Acid and Base

• Acid is a proton donor

• HF + H2O H3O+ + F-

• Base is a proton acceptor

NH3 + H30+ NH4++H20

Conjugate acid base pairs

Fill in the following table with the appropriate conjugate acid or base

Acid BaseH2SO4

PO43-

NH4+

F-

H20H20

Polyprotic acid

• Monoprotic HCl, Cl- • Diprotic H2S, HS-, S2-

• Diprotic H2SO4, HSO4-, SO4

2-

• Triprotic H3PO4, H2PO4-, HPO4

2-, PO43-

Naming acids

• Binary acids• Hydro ____________ ic acid

• Ternary acids• ______________ ic acid• ______________ous acid

Name the following acids

• H2S (aq)

• H2SO3

• HClO2

• HNO3

• HF(aq)

• HC2H3O2

Strong acids completely ionize in water

Strong acids (memorize)

Weak acids in waterare in equilibrium

They don’t completelyIonize in water

Strong acids: Completely ionize in water

Basesdonate OH-

or accept H+

• NaOH• Mg(OH)2

• Al(OH)3

• NH3

• PO43-

Neutralization reactions

Acid + base react to form salt + waterHCl + NaOH NaCl + H2O

H2SO4 + 2NaOH Na2SO4 + 2 H2O

How many moles of phosphoric acid are needed to react with 5.0 moles of sodium hydroxide?

Identify each of the following as an acid, base or salt

Acid Base Salt

HC2H3O2

MgCl2

H2SO4

Ca3(PO4)2

Sr(OH)2

Al(NO3)3

Complete the following neutralization reactions and balance

• HBr + NaOH

CaCl2 + H2O

Sr3(PO4)2 + H2O

pH=-log H3O+

Equations to determine pH

• Kw = [H30+][OH-] • Kw = 1x10-14

• pH = -log [H3O+]

• [H30+] = 10 –pH

Fill in the following graphpH [H3O+] [OH-] Acid/base?

6.60

1.8 x 10-3

2.91

3.89 x10-2

5.9 x 10-6

13.12

pH [H3O+] [OH-] Acid/base?

6.60 2.51 x 10-7 4.0x10-8 acid

11.1 5.6x10-12 1.8 x 10-3 base

2.91 1.23 x 10-3 8.13 x 10-12 acid

1.41 3.89 x10-2 2.57 x 10-13 acid

8.8 1.7 x 10-9 5.9 x 10-6 base

13.12 7.59 x 10-14 0.13 base

compound H3O+ OH - pH0.00000510 M HNO3

6.69x10-2 M KOH _____M HCl 2.3

Stomach produces HCl, how does it protect itself?

The acid in the stomach is hydrochloric acid, HCl, and has a pH of about 2.Acid of pH 2 can be quite corrosive - observe the effect of placing an iron nail in hydrochloric acid solution with pH =2

http://www.google.com/url?sa=i&rct=j&q=&esrc=s&source=images&cd=&cad=rja&uact=8&ved=&url=http://www.slideshare.net/SECBIO/digestion-29026783&psig=AFQjCNEGudpvrVBzwPG6KEb8A-DP5Tl5EA&ust=1444421314423080

http://www.google.com/url?sa=i&rct=j&q=&esrc=s&source=images&cd=&cad=rja&uact=8&ved=0CAcQjRxqFQoTCKDt9OPYs8gCFcgqiAod8u8JqA&url=http://slideplayer.com/slide/3383047/&psig=AFQjCNG2g-1rI0DO-Gn8NIEgLAO4g0LiCw&ust=1444421796846892

Buffer

• Buffer resists change in pH when small amounts of acid or base are added• A buffer is a solution containing either

a weak acid and its salt or a weak base and its salt, • Weak acid + its salt is the acid and its

conjugate base

Buffer system

Weak acid Salt of the acid(conjugate base)

A Buffer consists of

HSO4- and SO4

2-

NaOH is added to the solution.Who is the shark?

Did you pick HSO4-?

• Write the reaction

A Buffer consists of

H2CO3 and HCO3-

HCl is added to the solution.Who is the shark?

Predict whether each pair would form a buffer. Explain your answer.

Pairs of compounds

Explanation

KOH, KCl

HI, NaI

NH4I, NH3

NaH2PO4, H3PO4

Write an equation showing the buffering action of each of the following aqueous

solutions

• NH4I / NH3 adding OH-

• NaH2PO4/H3PO4 adding H3O+

Buffers in the body

The body has many systems to control pH ofthe blood