Ch. 2 - Acids & Bases

Question 1

What is a Bronsted-Lowry acid?

Answer 1

proton donor

Question 2

What is a Bronsted-Lowry base?

Answer 2

proton acceptor

Question 3

What must a BL acid have?

Answer 3

a hydrogen atom

Question 4

What must a BL base have?

Answer 4

a lone pair or pi bond

Question 5

What are counterions?

Answer 5

spectator ions (usually salts) that balance negative charge

Question 6

What is the possible net charge of BL acids?

Answer 6

negative, positive or zero

Question 7

What is the possible net charge of a BL base?

Answer 7

negative or zero

Question 8

What is an oxyacid?

Answer 8

acid in which the protons are placed on the oxygen

Question 9

What do you do when you see a salt in a reaction?

Answer 9

immediately split it into its ions and decide which ions are involved, make the other a spectator ion

Question 10

What does a loss of a proton form?

Answer 10

conjugate base

Question 11

What does the gain of a proton form?

Answer 11

conjugate acid

Question 12

What does a starting material with a positive net charge indicate?

Answer 12

it is an acid

Question 13

What does a starting material with a negative net charge indicate?

Answer 13

it is a base

Question 14

What is acid strength?

Answer 14

the tendency of an acid to donate a proton

Question 15

The stronger the acid, the ______ the Ka.

Answer 15

larger

Question 16

The stronger the acid, the ______ the pKa.

Answer 16

smaller

Question 17

What is the relationship between pKa and Ka?

Answer 17

pKa = -log(Ka)

Question 18

What is the pKa range for a typical organic compound?

Answer 18

+5 to +50

Question 19

What are the six strong acids? What are generally their pKas?

Answer 19

HCl, H2SO4, HBr, HNO3, HI, HClO4

negative pKas

Question 20

What are the common strong bases?

Answer 20

NaOH, KOH, LiOH (anything with -OH)

Question 21

How do you calculate Ka?

Answer 21

[products]/[reactants]

Question 22

A strong acid forms a ______ conjugate base.

Answer 22

weak

Question 23

A strong base forms a ______ conjugate acid.

Answer 23

weak

Question 24

What does the position of equilibrium rely on in acid/base reactions?

Answer 24

strength of acid/base

equilibrium will favor the formation of the weaker acid/base

Question 25

What is the general rule of acidity? (think stable!)

Answer 25

anything that stabilizes a conjugate base (A-) makes the starting acid more acidic

Question 26

What is the pKa of acetic acid (weak acid)?

Answer 26

5

Question 27

What is the pKa of water and alcohol?

Answer 27

16

Question 28

What is the pKa of ammonia (weak base)?

Answer 28

38

Question 29

What is the pKa of methyl amine?

Answer 29

40

Question 30

What is the pKa of methane/ethane?

Answer 30

50

Question 31

What are the four effects that make acids more acidic?

Answer 31

element, inductive, resonance, hybridization

Question 32

What is the most important factor of acidity?

Answer 32

element effects

Question 33

What are element effects?

Answer 33

the location of A (from HA) on the ptable rows: acidity increases as A is more EN (right) columns: acidity increases as A gets bigger (down)

Question 34

What are inductive effects?

Answer 34

presence of atoms that are more electronegative than carbon - withdraws electron density from C, pulls through sigma bonds - stabilizes negative charge >> acidity INCREASES with presence of electron withdrawing groups (more EN, closer to neg charge, greater the effect)

Question 35

What are resonance effects?

Answer 35

delocalization of electron density stabilizes conjugate bases and makes them weaker acidity of HA increases when conj base is resonance stabilized

Question 36

What are hybridization effects?

Answer 36

Lower hybridization (increased % s character) = more stable conj base and acid is more acidic

Question 37

How many bonds are formed in an acid-base reaction?

Answer 37

one

Question 38

Does an atom with a filled octet have an available electron pair?

Answer 38

no

Question 39

Can unpaired electrons be used in acid-base reactions?

Answer 39

no

Question 40

Equilibrium tends to the side with a ______ Ka value?

Answer 40

smaller

Question 41

What is the correct formula for the conjugate acid of CH3NH2?

Answer 41

CH3NH3+

Question 42

What is the cause of the inductive effect?

Answer 42

the difference of EN of the atoms involved

Question 43

In an acid-base reaction, the equilibrium always favors the formation of what species?

Answer 43

weak acids and weak bases

Question 44

Acid strength is ______ by any factor that makes the conjugate base more stable.

Answer 44

increased

Question 45

What is an an electrophile?

Answer 45

an electron-deficient species

Question 46

What is a nucleophile?

Answer 46

an electron-rich species

Question 47

What is TsOH and what is it's pKa?

Answer 47

p-toluenesulfonic acid, strong organic acid with pKa of -7

Question 48

What are the three common types of bases?

Answer 48

negative charged oxygen bases (-OH + derivatives) negative charge nitrogen bases (-NH2 + derivatives) hydrife (H-)

Question 49

What are pKa values of strong bases?

Answer 49

pKa > 12

Question 50

Do all strong bases have a negative charge?

Answer 50

Yes, but not all species with a negative charge are strong bases.

Question 51

What is a carbanion?

Answer 51

negatively charged carbon atom

Question 52

What is a Lewis acid?

Answer 52

electron pair acceptor

Question 53

What is a Lewis base?

Answer 53

electron pair donor

Question 54

What must a Lewis base have?

Answer 54

available electron pair or pi bonds

Question 55

T/F: All BL acids are Lewis acids?

Answer 55

True, but not all Lewis acids are BL acids

Question 56

How many bonds are broken and formed in a Lewis reaction?

Answer 56

one formed, none broken (forms lewis acid-base complex)