GenChem10 (Acids and Bases)

Question 1

An indicator which turns red in acidic solution and blue in basic solution

Answer 1

Litmus Paper

Question 2

Defines acids as a species that produces H+ (a proton) in an aqueous solution and a base as a species that produces OH- (a hydroxide ion) in an aqueous solution.

Answer 2

Arrhenius Definition

Question 3

Defines acids as a species that donates protons, and a base as a species that accepts protons.

Answer 3

Bronsted-Lowry Definition

Question 4

Defines an acid as an electron pair acceptor and a base as an electron pair donor.

What are the exceptions?

Answer 4

Lewis Definition

BCl3 and AlCl3

Question 5

Acids formed from anions whose names end in ide have the prefix _____ and the ending ___

Answer 5

hydro, ic

hydrofluoric acid - HF
hyrdobromic acid -HBr

Question 6

Acids formed from oxyanions are called

If the oxyanion ends in -ite, it has more/less oxygen and the acid ends in ______

If an oxyanion ends in -ate, it has more/less oxygen and the acid ends in

Answer 6

oxyacids

An oxyanion ending in -ite has less oxygen and the acid ends in -ous.

An oxyanion ending in -ate has more oxygen and the acid ends in -ic

Question 7

ClO-
ClO2-
ClO3-
ClO4-
NO2-
NO3-

Answer 7

ClO-Hypocholorite
ClO2- Chlorite
ClO3-Chlorate
ClO4-Perchlorate
NO2-Nitrite
NO3-Nitrate

Question 8

HClO
HClO2
HClO3
HClO4
HNO2
HNO3

Answer 8

Hypochlorous acid
Chlorous Acid
Chloric Acid
Perchloric Acid
Nitrous Acid
Nitric Acid

Question 9

If Ka= 1.8*10^-5, what is pka?

Answer 9

slightly less than 5

exactly 4.74

Question 10

What property do strong acids and bases have?

Answer 10

They completely dissociate into there component ions in aqueous solution

Question 11

Name the strong acids that you should be aware of

Answer 11

HCl
HBr
HI
HNO3
HClO3
HClO4
H2SO4

Question 12

What is an amphoteric (amphoprotic) compound?

Answer 12

It can be an acid or base

ex) HCO3-

Question 13

The stronger an acid the weaker/stronger the base

Answer 13

Weaker the base!

Question 14

Name the strong bases that you should be aware of.

Answer 14

Group I and II metal hydroxides

LiOH
NaOH
KOH
RbOH
CsOH

Ca(OH)2
Sr(OH)2
Ba(OH)2
Magnesium not included because it’s not soluble

Question 15

What is the equation for Ka?

Answer 15

Ka=[H30+][A-]/([HA])

Question 16

What is the equation for Kb?

Answer 16

Kb=[B+][OH-]/[BOH]

Question 17

A reaction with acids and bases reacting with each other, forming a salt and often water

Answer 17

Neutralization Reaction

Ex: HA + BOH —> BA + H2O

Question 18

A reaction in which salt ions react with water to give back an acid or base, also considered the reverse of a neutralization reaction

Answer 18

Hydrolysis

Question 19

What are the 4 combinations of strong and weak acids/bases?

Answer 19

SA/SB
SA/WB
WA/SB
WA/WB

Question 20

What are the products of a reaction between equal concentrations of a SA and SB?

What is the resulting pH?

Do the resulting ions react with water?

Answer 20

Salt and water

pH=7 (neutral)

No

Question 21

What is the product of a reaction between a strong acid and a weak base?

Answer 21

Salt, usually no water

Question 22

What happens when HCl reacts with NH3 in aqueous solution?

Why does this occur?

Answer 22

NH3 + HCL —> NH4(+) + CL(-)
NH4(+) + H2O —-> NH3 + H3O(+)

The conjugate acid (NH4+) is stronger than the conjugate base (CL-) of the strong acid HCL. NH4 reacts with OH, producing an excess of H+.

Question 23

What is the product of a reaction between an weak acid and a strong base?

Answer 23

A basic solution

Question 24

What is the product of a reaction between a weak acid and a weak base?

Answer 24

It depends upon the Ka and Kb for the reactants, whichever is higher will cause the solution to be acidic or basic

Question 25

What is the one diprotic strong acid? How many acid equivalents does it produce?

Answer 25

H2SO4 2

Question 26

What is the normality of a concentration of 2M H3PO4?

Answer 26

6N

Question 27

What is the equivalent weight of H2SO4 (molecular weight = 98g/mol)

Answer 27

49 g; that is, 49 g of H2SO4 releases 1 acid equivalent

Question 28

A species that can act as an acid or a base, depending upon its chemical environment, is called

Answer 28

amphoteric or amphiprotic Ex) Water

Question 29

When water reacts as a base, it behaves as an When water react with an acid, it behaves as a

Answer 29

Acid H2O + B- -----> NH + OH- Base H2O + HA ----> H3O(+) + A-

Question 30

The conjugate base of a polyprotic acid is usually

Answer 30

amphoteric ex) HSO4

Question 31

The hydroxides of certain metals (Al, Zn, Pb, Cr) are

Answer 31

Amphoteric

Question 32

A procedure used to determine the molarity of an acid or base. It is accomplished by reacting a known volume of a solution of an unknown concentration with a known volume of a solution of a known concentration

Answer 32

Titration

Question 33

In titration, the point at which the acid equivalents equal the base equivalents is known as the Does this point always occur at pH of 7?

Answer 33

Equivalence point No, only for strong acids/strong base titrations

Question 34

Under what conditions are there several equivalence points?

Answer 34

When titrating polyprotic acids or bases

Question 35

Weak organic acids or bases that have different colors in their undissociated and dissociated states. Used in titrations, are in low concentration and don't alter the equivalence point

Answer 35

Indicator

Question 36

The point at which the indicator changes color is called the This is not the equivalence point, can the volume of the endpoint be used?

Answer 36

End point Because there is very little difference in volume between the equivalence point and the end point (look at the graph on p. 397), and it may be corrected for or ignored.

Question 37

What is the equation to calculate the volume added in a titration using normality? What is the equation for normality? What about gram equivalents?

Answer 37

VaNa=VbNb gram equivalents/volume of solution gram equivalents

Question 38

How is the titration curve of a weak acid using a strong base different from a strong acid using a strong base?

Answer 38

The pH is higher at the beginning and the pH changes most significantly early on. Importantly, the equivalence point is in the basic range.

Question 39

Consists of a mixture of a weak acid and its salt, or a mixture of a weak base and its salt.

Answer 39

Buffer Solution ex: acetic acid (CH3COOH) and its salt (CH3COO-Na+) ammonia (NH3) and its salt ammonium chloride (NH4+ CL-)

Question 40

What is the equation used to estimate the pH of a solution in the buffer region where the concentrations of the species and its conjugate are present in approximately equal concentrations For a weak acid buffer solution: For a weak base buffer solution:

Answer 40

pH=pKa + log[conjugate base]/[weak acid] pH=pKb + log[conjugate acid]/[weak base]