Properties of Acids and Bases

1

Bell Ringer

• Watch the video and answer the questions
• https://ed.ted.com/lessons/the-strengths-and-weaknesses-of-acids-
and-bases-george-zaidan-and-charles-morton

2

Some Properties of Acids

þ Produce H+(as H3O+) ions in water (the hydronium ion is a

hydrogen ion attached to a water molecule)

þ Taste sour

þ Corrode metals

þ Electrolytes

þ React with bases to form a salt and water

þ pH is less than 7

þ Turns blue litmus paper to red “Blue to Red A-CID”

3

Some Properties of Bases



Produce OH

-

ions in water



Taste bitter, chalky



Are electrolytes



Feel soapy, slippery



React with acids to form salts and water



pH greater than 7



Turns red litmus paper to blue “

B

asic

B

lue”

Multiple Choice

What tastes Sour?

• Acids

• Bases

• Salts

• All

Multiple Choice

What feels slippery?

• Acids

• Bases

• All

5

Acid/Base definitions

• Definition #1: Arrhenius (traditional)

Acids – produce H+ions (or hydronium ions

H3O+)

Bases – produce OH-ions

(problem: some bases don’t have hydroxide

ions!)

6
Arrhenius acid is a substance that produces H+ (H3O+) in water

Arrhenius base is a substance that produces OH-in water

Multiple Choice

According to Arrhenius, what is the definition of an ACID?

• a substance that contains hydroxide and ionizes to produce OH-

• a substance that contains hydrogen and ionizes to produce H+

• a substance that contains hydrogen and ionizes to produce OH-

• a substance that contains hydroxide and ionizes to produce H+

Multiple Choice

NaOH is:

• an Arrhenius base

• an Arrhenius acid

• neither an acid nor a base

• both an acid and a base

Multiple Choice

If a solution is basic which ion will be more present?

• H+

• K+

• OH-

• H-

7

Acid/Base Definitions

• Definition #2: Brønsted – Lowry

Acids – proton donor

Bases – proton acceptor

A “proton” is really just a hydrogen

atom that has lost its electron!

A Brønsted-Lowry acid is a proton donor

A Brønsted-Lowry base is a proton acceptor

​

Bronsted-Lowry

9

Conjugate Pairs

Multiple Choice

What is the conjugate base of HCO₃^-?

• HCO₃^-

• H₂CO₃^-

• H₂CO₃

• CO₃^2-

Multiple Choice

What is the conjugate base in the following reaction?

• HCO₃^-1

• HCl

• H₂CO₃

• Cl^-1

10

Learning Check!

Label the acid, base, conjugate acid, and

conjugate base in each reaction:

HCl + OH

-

→

Cl

-

+ H

2

O

H

2

O + H

2

SO

4

→

HSO

4

-

+ H

3

O

+

11

Acid-Base Reactions

• Also known as neutralization

reactions.

• Will always produce a salt and

water.

• Salt means an ionic

compound.

12

Example

HCl + NaOH → NaCl + H2O

Acid Base

Salt Water

H2SO4 + 2KOH → K2SO4 + 2H2O

Acid

Base

Salt

Water

Multiple Choice

This image represents

• Neutralization reaction

• synthesis

• decompostion

• single displacement

13

The

pH scale

is a way of

expressing the strength

of acids and bases.

Under 7 = acid

7 = neutral

Over 7 = base

Multiple Choice

All solutions that fall between 0 and 6.9 are

• Acids

• Bases

• Neutral

• Phytoplankton

Multiple Choice

Which is most acidic?

• milk

• Lemon Juice

• bleach

Multiple Choice

What is the range of pH values in a basic solution?

• 0-6

• 8-14

• 7

• 0-14

Multiple Choice

Which of these solutions is an acid?

• Dish Soap: pH of 12

• Tomato Soup: pH of 4

• Baking Soda: pH of 9

• Drain Cleaner: pH of 14

14

•

Weak acids

are much less than 100% ionized in

water.

One of the best known is acetic acid = CH

3

CO

2

H

Strong and Weak Acids/Bases

15

•

Strong Base:

100% dissociated in

water.

NaOH (aq)

---

> Na

+

(aq) + OH

-

(aq)

Strong and Weak Acids/Bases

Other common strong

bases include KOH,

LiOH

,

RbOH

,

CsOH

,

Sr

(OH)

2

,

Ba(OH)

2

and

Ca(OH)

2

.

16

•

Weak base:

less than 100% ionized

in water

One of the best

-

known weak bases is

ammonia

NH

3

(aq) + H

2

O (l)

→

NH

4

+

(aq) + OH

-

(aq)

Strong and Weak Acids/Bases

Multiple Choice

Strong acids and bases...

• do not break apart into ions (non-electrolyte)

• partially break apart into ions (weak electrolyte)

• completely break apart into ions (non-electrolyte)

• completely break apart into ions (strong electrolyte)

Multiple Choice

The table shows the pH of several solutions. Which solution is the most acidic?

• vinegar

• milk

• water

• bleach