• In aqueous solution…In aqueous solution…

HCl(aq) H+(aq)+ Cl-(aq)

AcidsAcids increase hydrogen ion concentration [H+]

Courtesy Christy Johannesson www.nisd.net/communicationsarts/pages/chem

BasesBases increase hydroxide ion concentration [OH-]

KOH (aq) K+(aq)+ OH-

(aq)

H2O can function as both an ACID and a

BASE.

Equilibrium constant for water = Kw

Kw = [H+] [OH-] = 1.00 x 10-14 at 25 oC

pH

pOH

[H+]

[OH-]

pH + pOH = 14

pH = -log[H+]

[H+] = 10-pH

pOH = -log[OH-]

[OH-] = 10-pOH

Kw = [H+] [OH-] = 1 x10-14

OH-

H+OH-

OH-H+

H+

[H+] = [OH-] [H+] > [OH-] [H+] < [OH-] acidic

solutionneutralsolution

basicsolution

co

nc

en

trat

ion

(m

ole

s/L

)

10-14

10-7

10-1

Timberlake, Chemistry 7th Edition, page 332

pH = 3

pH = 7

pH = 12

pH + pOH = 14pH + 11.09 = 14

Solution is acidic

pH = 14 – 11.09 = 2.91

Solution is basic

Kw = [H+] [OH-] = 1.0 x10-14

1.0 x10-14 = [3.3 x 10-10] [OH-]

[OH-] = 3.0 x 10-5 M

pH = - log [H+] = -log [0.240M H+]

pH = 0.620

pH = - log [H+]

4.60 = -log [H+]

[H+] = 2.51 x 10-5 M2nd log -4.6

You can check your answer by working backwards.

pH = - log [2.51x10-5 M]

pH = 4.60

10- 4.60

Timberlake, Chemistry 7th Edition, page 335

1.0 MHCl0

gastricjuice1.6

vinegar2.8

carbonated beverage3.0

orange3.5

apple juice3.8

tomato4.2

lemonjuice2.2 coffee

5.0

bread5.5

soil5.5

potato5.8

urine6.0

milk6.4

water (pure)7.0

drinking water7.2

blood7.4

detergents8.0 - 9.0

bile8.0

seawater8.5

milk of magnesia10.5

ammonia11.0

bleach12.0

1.0 MNaOH(lye)14.0

8 9 10 11 12 14133 4 5 621 70

acidic neutral basic[H+] = [OH-]

14 1 x 10-14 1 x 10-0 0 13 1 x 10-13 1 x 10-1 1 12 1 x 10-12 1 x 10-2 2 11 1 x 10-11 1 x 10-3 3 10 1 x 10-10 1 x 10-4 4 9 1 x 10-9 1 x 10-5 5 8 1 x 10-8 1 x 10-6 6

6 1 x 10-6 1 x 10-8 8 5 1 x 10-5 1 x 10-9 9 4 1 x 10-4 1 x 10-10 10 3 1 x 10-3 1 x 10-11 11 2 1 x 10-2 1 x 10-12 12 1 1 x 10-1 1 x 10-13 13 0 1 x 100 1 x 10-14 14

NaOH, 0.1 MHousehold bleachHousehold ammonia

Lime waterMilk of magnesia

Borax

Baking sodaEgg white, seawaterHuman blood, tearsMilkSalivaRain

Black coffeeBananaTomatoesWineCola, vinegarLemon juice

Gastric juice

Mor

e ba

sic

Mor

e ac

idic

pH [H1+] [OH1-] pOH

7 1 x 10-7 1 x 10-7 7

6 5 .

7

3 4 1 2