Acids and BasesAcids and Bases

““Tragedy is like strong Tragedy is like strong acidacid -- it dissolves away all but the -- it dissolves away all but the very gold of truth. very gold of truth.

” - D.H. Lawrence” - D.H. Lawrence

Characteristics of AcidsCharacteristics of Acids

Taste _______________. Taste _______________. Conduct __________________________Conduct __________________________ Cause _______________________Cause _______________________ React with ________ to form ________ React with ________ to form ________ React with _____________ to form React with _____________ to form

_____ and a ________. _____ and a ________. Produce ___ ions in water. Produce ___ ions in water.

Characteristics of BasesCharacteristics of Bases

Taste _____________ Taste _____________ Slippery. Slippery. Can be _______________ Can be _______________ Produce ___________ in water. Produce ___________ in water. React with acids to produce _______ React with acids to produce _______

and a __________.and a __________.

Naming Acids and BasesNaming Acids and Bases

Acids – Compounds that dissociate in Acids – Compounds that dissociate in water to give Hwater to give H++ ions ions

Generic acid formula: _________Generic acid formula: _________ H – __________H – __________ n – numbern – number

If n = 1, acid is If n = 1, acid is monoproticmonoprotic If n = 2, acid is If n = 2, acid is diproticdiprotic If n = 3, acid is If n = 3, acid is triprotictriprotic

X – monatomic or polyatomic ______X – monatomic or polyatomic ______

Naming AcidsNaming Acids

Rules for naming acids:Rules for naming acids: IF:IF:

X ends in X ends in ____________, name is , name is ______________________ acid.acid.

X ends in ______, name is _________ acid.X ends in ______, name is _________ acid.

X ends in ______, name is _________X ends in ______, name is _________ acid.acid.

Naming AcidsNaming Acids

Try these:Try these: HFHF HNOHNO33

HIHI HH22COCO33

HClOHClO44

HH22SOSO33

Naming BasesNaming Bases

Bases – Compound that produces OHBases – Compound that produces OH-- ions ions when dissolved in waterwhen dissolved in water

Names the same as any other ionic Names the same as any other ionic compound.compound.

Examples:Examples:

Note: Ammonia (NHNote: Ammonia (NH33) is a base, even ) is a base, even though it is not a hydroxidethough it is not a hydroxide

Hydrogen Ions and AcidityHydrogen Ions and Acidity

Self ionization of water:Self ionization of water:

HH22O O ↔ ↔ HH+ + + OH+ OH--

In a neutral solution: In a neutral solution:

[H[H++] = [OH] = [OH--] = ____________] = ____________ So:So:

[H[H++] [OH] [OH--] = ______________] = ______________

Hydrogen Ions and AcidityHydrogen Ions and Acidity

In acidic solutions:In acidic solutions:

[H[H++] > [OH] > [OH--]]

[H[H++] >__________] >__________ In basic (alkaline) solutions:In basic (alkaline) solutions:

[H[H++] < [OH] < [OH--]]

[H[H++] <__________] <__________

Hydrogen Ions and AcidityHydrogen Ions and Acidity

It’s so hard saying “a concentration It’s so hard saying “a concentration of one times ten to the negative of one times ten to the negative seventh molar” all the time…Is there seventh molar” all the time…Is there a better way?a better way?

YES! All we need is the exponent…YES! All we need is the exponent…

So if the concentration of hydrogen So if the concentration of hydrogen ions is _________, the pH = __ions is _________, the pH = __

pHpH

What is the pH if [HWhat is the pH if [H++] =] = 1 x 101 x 10-6 -6 MM 1 x 101 x 10-10-10 M M 2 x 102 x 10-7 -7 MM 3.75 x 103.75 x 10-3 -3 MM

What is the [HWhat is the [H++] if the pH =] if the pH = 44 99 5.55.5 13.513.5

pHpH

pH has a range of 0 pH has a range of 0 to 14to 14

pH < 7, solution is pH < 7, solution is __________________

pH > 7, solution is pH > 7, solution is __________________

pH = 7, solution is pH = 7, solution is __________________

pH is measured pH is measured with an indicator or with an indicator or pH meter.pH meter.

pH of Some Common SubstancespH of Some Common Substances

Is there a pOH?Is there a pOH?

Sure! It’s pretty much the same Sure! It’s pretty much the same thing.thing.

pOH = _________pOH = _________ Since [HSince [H++] [OH] [OH--] = 1 x 10] = 1 x 10-14 -14 MM22

pH + pOH = ____pH + pOH = ____

Strong vs. Weak Acids Strong vs. Weak Acids

Strong DOES NOT mean concentrated!Strong DOES NOT mean concentrated! Some acids only partially dissociate in Some acids only partially dissociate in

water. E.g. Acetic acid. These are ______ water. E.g. Acetic acid. These are ______ acids. acids.

HCHC22HH33OO2 2 ‹-› H‹-› H++ + C + C22HH33OO22--

Acids that completely dissociate in Acids that completely dissociate in water are _______ acids. E.g. water are _______ acids. E.g. Hydrochloric acidHydrochloric acid

HCl HCl → H→ H++ + Cl + Cl--

Strong vs. Weak AcidsStrong vs. Weak Acids

Acids can be STRONG and Acids can be STRONG and ConcentratedConcentrated

12M HCl12M HCl Acids can be STRONG and DiluteAcids can be STRONG and Dilute

0.01M HNO0.01M HNO33

Acids can be WEAK and ConcentratedAcids can be WEAK and Concentrated

12M H12M H22COCO33

Acids can be WEAK and DiluteAcids can be WEAK and Dilute

0.01M HC0.01M HC22HH33OO22

How can you tell if an acid is How can you tell if an acid is strong?strong?

Look for the Acid Dissociation Look for the Acid Dissociation constant, __constant, __

So large KSo large Kaa = _______ acid. = _______ acid. Small KSmall Kaa = _______ acid = _______ acid

Neutralization ReactionsNeutralization Reactions

Acids and Bases react to form water and a Acids and Bases react to form water and a salt.salt.

The products are neutral if the number of The products are neutral if the number of moles of Hmoles of H+ + = moles of OH= moles of OH--

This is referred to as the This is referred to as the _________________._________________. If we add a volume of a known concentration If we add a volume of a known concentration

of an acid/base to a volume of an unknown of an acid/base to a volume of an unknown concentration of base/acid, we can concentration of base/acid, we can determine the unknown’s concentration.determine the unknown’s concentration.

This process is known as This process is known as _____________._____________.

TitrationsTitrations Titrations use indicator Titrations use indicator

dyes to determine if the dyes to determine if the solutions have been solutions have been neutralized.neutralized.

___________ – Point at ___________ – Point at which the indicator which the indicator changes color and the changes color and the titration is stopped.titration is stopped.

____________ and ____________ and ______________ are not the ______________ are not the same thing. However, the same thing. However, the goal of a titration is to goal of a titration is to have the end point as have the end point as close to the equivalence close to the equivalence point as possible.point as possible.

So how do we use titrations?So how do we use titrations?

We can find the concentration of a We can find the concentration of a solution is we have a solution of solution is we have a solution of known concentration.known concentration.

Let’s say we have neutralize 25 mL Let’s say we have neutralize 25 mL of Hof H22SOSO44 solution with 18 mL of 1.0 M solution with 18 mL of 1.0 M NaOH solution. What is the NaOH solution. What is the concentration of the Hconcentration of the H22SOSO44??

TitrationsTitrations

First, we need to write a balanced First, we need to write a balanced equation.equation.

Acid Base

TitrationsTitrations

Given: VGiven: VAA= 25 mL, M= 25 mL, MBB= 1.0M, V= 1.0M, VBB=18 mL=18 mL Next, you can use the following Next, you can use the following

relationship:relationship:

Where __ is the coefficient from the Where __ is the coefficient from the reaction, __ is molarity, __ is volume, __ reaction, __ is molarity, __ is volume, __ is the acid, and __ is the base.is the acid, and __ is the base.

TitrationsTitrations