CHM CH. 2 Connect

Which of the following species are common negatively charged strong bases? Select all that apply.

-NH2 -H -OH

Which of the following structural characteristics is required for a compound to act as a Bronsted-Lowry base?

an available electron pair

Acid-base reactions exemplify a general trend of reactivity. The base is an electron-_____ species that reacts readily with the electron-_____ acid.

rich, deficient

An acid ionizes in aqueous solution according to the equation HA + H2O ⇄ A- + H3O+. A large value for Ka indicates that the equilibrium lies far to the _____ and implies that the acid is ______.

right, strong

Which statement(s) correctly describe(s) aspirin, and the proton transfer reaction that converts aspirin to its conjugate base (shown)?

If NaOH was used as the base, then the ionic form of aspirin would be favored at equilibrium. Aspirin is a weak acid.

Which of the following statements describes a Lewis acid-base reaction correctly?

The base donates an electron pair to the acid.

For a base of formula A:-, as the s character of the orbital containing the lone pair increases, the stability of the base _____ and the strength of its conjugate acid HA _____.

increases, increases

Select all species in the diagram that can function as Bronsted-Lowry bases.

B, C, D

Which of the following is the MOST important factor that determines the acidity of an H-A bond?

The location of element A in the periodic table

Which of the following are commonly used as bases in organic reactions? (Select all that apply.)

lithium diisopropylamide butyllithium OH and its organic derivatives triethylamine

Which of the following statements correctly describe Bronsted-Lowry acids? (Select all that apply.)

A Bronsted-Lowry acid is a proton donor. A Bronsted-Lowry acid must contain a H atom.

Which of the following conjugate bases are stabilized by resonance? (Select all that apply.)

A, C

Which of the following correctly describes the term "acid strength"?

The tendency of an acid to donate a proton

Which of the following species commonly act as Lewis acids in organic reactions? (Select all that apply.)

BF3 AlCl3

Acid strength is a measure of how readily a compound donates a(n) ______

proton

Which of the following Bronsted-Lowry acid-base reactions is drawn correctly?

C

Which of the following statements correctly describe the relationship between acids and bases and their conjugates? (Select all that apply.)

A strong acid generally forms a weak conjugate base. There exists an inverse relationship between acid strength and conjugate base strength.

Without using a Ka or pKa table, rank the three compounds shown based on increasing acidity. Place the least acidic molecule at the top of the list.

A, C, B

Select all statements that accurately describe Bronsted-Lowry acid-base reactions.

Acid-base reactions are also known as proton transfer reactions. One bond is formed in an acid-base reaction.

Which of the following statements correctly describe periodic trends in the acidity of an acid with the general formula HA? (Select all that apply.)

Acidity of HA increases as atom A moves from left to right across a period. Acidity of HA increases as atom A moves down a group.

Select all statements that correctly describe Lewis and Bronsted-Lowry acids and bases.

All Bronsted-Lowry acids are Lewis acids. Not all Lewis acids are Bronsted-Lowry acids.

Which of the statements below correctly describe the curved arrows required to show the mechanism of the following acid-base reaction correctly? (Select all that apply.)

An arrow must begin on one of the bonds between H and O and end on O. An arrow must begin on the lone pair of the acetylide and end on a hydrogen of H2O.

A base such as the acetate anion (shown) exists as a resonance hybrid, which means that electrons are over several atoms. Such a structure is stabilized by and is therefore a base than one with a localized charge.

Blank 1: delocalized, spread, or dispersed Blank 2: resonance or delocalization Blank 3: weaker

The name of the compound shown is ______ acid, which is often abbreviated as _________.

Blank 1: tosylic, p-toluenesulfonic, para-toluenesulfonic, p-toluenesulphonic, or para-toluenesulphonic Blank 2: TsOH, PTSA, or p-TsOH

Which of the following Bronsted-Lowry acid/base classifications are correct? (Select all that apply.)

CH3COOH is an acid. (CH3)3N is a base.

Which of the following is the correct formula for the conjugate acid of CH3NH2?

CH3NH3+

Which of the following acids have a conjugate base stabilized by resonance? (Select all that apply.)

ClCH2COOH CH3CH2CN

The structure of p-toluenesulfonic acid most closely resembles the structure of _____.

H2SO4

Select all statements that correctly describe the acid-base chemistry of aspirin and its biological implications.

In the basic environment of the small intestine, aspirin is deprotonated to form its conjugate base. Aspirin contains a carboxylic acid functional group.

Which of the following statements correctly describe the inductive effect? (Select all that apply.)

Inductive effects operate through σ bonds. This effect is the result of electronegativity differences between atoms.

A Bronsted-Lowry base must have an "available" electron pair to form a bond to H+. Which of the following structural features allow an electron pair to be used in this way? (Select all that apply.)

One or more lone pairs in the structure One or more electron pairs in π bonds

Which of the following statements correctly describe the steps involved in any general reaction between a Bronsted-Lowry acid and base (see the diagram)? (Select all that apply.)

The acid (H-A) loses a proton, leaving an electron pair on atom A. The electron pair of the base (B:) forms a new bond to H.

When comparing the acidity of two acids (for example, H-A and H-B), which of the following should be considered FIRST?

The acidity of H-A and H-B based on the location of A and B in the periodic table

Which of the following statements correctly describes the process that occurs in a Lewis acid-base reaction?

The base uses its electron pair to form a new covalent bond to the acid.

Which of the following statements correctly explains how the conjugate base of an acid may be resonance stabilized?

The negative charge is stabilized by delocalization through the π framework.

According to the Bronsted-Lowry definition, an acid must contain which of the following?

a hydrogen atom

When identifying Bronsted-Lowry acids and bases in an organic reaction, if only one species has a lone pair or π bond it must be the _____, while if only one species contains an available hydrogen atom it must be the _____.

base, acid

In a Lewis acid-base reaction, the base _____ an electron pair to/from the acid. This is an example of a general reaction trend, i.e., that electron-rich species react with electron-_____ species.

donates, deficient

In a Lewis acid-base reaction, the base donates a(n) __________ pair to form a new __________ bond between the base and the acid.

electron, covalent

Match each compound with the correct description of its behavior as an acid.

h2o is a lewis acid and BL acid

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

increased

The acidity of acid H-A ______ as atom A moves from left to right across a period and _________ down a group in the periodic table.

increases, increases

The pull of electron density through σ bonds is called the ______ effect and is caused by a difference in the ______ of the atoms of the atoms involved

inductive, electronegativity

In many acid-base reactions a starting material with a net _____ charge is usually an acid while a starting material with a net _____ charge is often a base.

positive, negative

In a proton transfer reaction, equilibrium will favor the _____ if the reacting acid and base are strong. Since a strong acid and base form a _____ conjugate acid and base, the reaction will favor the formation of the _____ acid and base.

products, weak, weaker

Consider a conjugate base of the general formula A-. Rank the conjugate base in order of decreasing stability in terms of the hybrid orbital in which the lone pair of A- is located. Place the most stable situation at the top of the list and the least stable situation at the bottom of the list.

sp, sp2, sp3

If NaOH was used as the base, then the ionic form of aspirin would be favored at equilibrium. Aspirin is a weak acid.

strong inorganic acid----> HCl strong organic acid ----->p-toluenesulfonic acid (TsOH) weak organic base ----->pyridine strong organic base---->(butyllithium) CH3CH2CH2CH2-Li+ (butyllithium)

A _____ acid is one that readily donates a proton. Its conjugate base will be _____ ready to accept a proton and will therefore be a relatively _____ base.

strong, less, weak

In an acid-base reaction, the equilibrium always favors the formation of what species? (Select all that apply.)

weak acids weak bases

A strong acid has a relatively _____ conjugate base that forms readily and is therefore _____ stable than the conjugate base of a weak acid. Anything that _____ the stability of a conjugate base makes the starting acid more acidic.

weak, more, increases