11 Acids and Bases

Question 1

Arrhenius Definition of acid

An acid is a substance that

Answer 1

ionizes in water and produces hydrogen ions (H⁺ ions)

Question 2

Arrhenius definition of Bases

A base is a substance that

Answer 2

ionizes in water and produces hydroxide ions (OH^- ions)

Question 3

Bronsted-Lowry definition of an acid

An acid is a substance that is capable

Answer 3

of donating a proton, which is the same as donating an H+ ion.

Question 4

Bronsted-Lowry definition of Base

A base is a substance that is capable of

Answer 4

accepting a proton.

Question 5

Lewis definition of an acid

An acid is an electron pair

Answer 5

acceptor.

Question 6

Lewis definition of a base

A base is an electron pair

Answer 6

donor.

Question 7

p(anything) = -log(anything)

pH =

pOH =

pK_a =

pK_b =

Answer 7

• log(H⁺)
• log(OH^-)
• log K_a
• log K_b

Question 8

In a solution

When [H⁺] = [OH^-],

Answer 8

the solution is neutral, and pH = 7

Question 9

In a solution when [H⁺] is greater than [OH^-],

Answer 9

the solution is acidic, and the pH is less than 7

Question 10

In a solution when [H+] is less than [OH-],

Answer 10

the solution is basic, and the pH is greater than 7.

Question 11

Acid Dissociation Constant

K_a =

Answer 11

([H+][A-]) / [HA]

[H⁺] = molar concentration of hydrogemn ions (M)

[A^-] = molar concentration of conjugate base ions (M)

[HA] = molar concentration of undissociated acid molecules (M)

Question 12

Base Dissociation Constant

K_b =

Answer 12

([HA⁺][OH^-]) / [B]

[HA+] = protonated base ions (M)

[OH-] = molar concentration of hydroxide ions (M)

[B] = unprotonated base molecules (M)

Question 13

Important Strong Acids

Answer 13

HCl, HBr, HI, HNO₃, HClO₄, H₂SO₄

Question 14

Important Strong Bases

Answer 14

LiOH, NaOH, KOH, Ba(OH)₂, Sr(OH)2

Question 15

If a salt is composed of the conjugates of a strong base and a strong acid

Answer 15

its solution will be neutral.

Question 16

If a salt is composed of the conjugates of a weak base and a strong acid,

Answer 16

its solution will be acidic.

Question 17

If a salt is composed of the conjugates of a strong base and a weak acid

Answer 17

its solution will be basic

Question 18

If a salt is composed of the conjugates of a weak base and a weak acid,

Answer 18

the pH of its solution will depend on the relative strengths of the conjugate acid and base of the specifics ions in the salt.

Question 19

The Henderson-Hasselbalch Equation

pH =

Answer 19

pKa + log([A-] / [HA])

[HA] = molar concentration of undissociated weak acid (M)

[A^-] = molar concentration of conjugate base (M)

pOH = pK_b + log([HB⁺] / [B]

[B] = molar concentration of weak base (M)

[HB+] = molar concentration of conjugate acid (M)

Question 20

Polyprotic Acids

Answer 20

Acids that can give up more then one hydrogen.

Question 21

Amphoteric substances

Answer 21

substances that can act as either an acid or a base.

Question 22

An Acid Anhydride is

Answer 22

a substance that combines with water to form an acid.

Question 23

A basic Anhydride is

Answer 23

a substance that combines with water to form a base.

Question 24

Neutralization reaction

Answer 24

Acid + Base = Water + Salt

Question 25

In a good buffer solution

pH =

Answer 25

pKa

and

pOH = pKb

Question 26

pK_a + pKb =

Answer 26

14

Question 27

k_ak_b =

Answer 27

1 X 10^-14

Question 28

pH + pOH =

Answer 28

14

Question 29

The equivalence point is

Answer 29

the point in titration when exactly enough base has been added to neutralize all the acid that was initially present.

Question 30

When a strong acid is added to a weak base(or vice versa), before reaching the equivalence point, the reaction goes through a buffer region.

At the point when exactly half of the acid is converted into the conjugate base, is the

Answer 30

half equivalence point. At this point pH = pK_a

Question 31

Examples of Lewis Acids

All

Answer 31

Cations are Lewis acids since they are able to except electrons

An atom, ion, or molecule with an incomplete octet of electrons can act as an lewis acid.

Molecules where the central atom can have more than 8 valence shell electrons can be electron acceptors, and thus are classified as lewis acids.

Molecules that have multiple bonds between two atoms of different electronegativities.

Question 32

An atom, ion, or molecule with a lone-pair of electrons can be a

Answer 32

lewis base.

Question 33

An electrolyte is any substance containing free ions that

Answer 33

make the substance electrically conductive.