Chapter 3: Acids and Bases

Question 1

What is a Bronsted-Lowry acid?

Answer 1

A proton donor

Question 2

What is a Bronsted-Lowry base?

Answer 2

A proton acceptor

Question 3

Describe the reaction mechanism for acid/base reactions.

Answer 3

A reaction mechanism utilizes curved arrows to show the flow of electrons that account for a chemical reaction. The mechanism of proton transfer always involves at least two curved arrows.

Question 4

How is pKa related to the strength of an acid?

Answer 4

A strong acid has a low pKa, while a weak acid has a high pKa.

Question 5

Does equilibrium favor the formation of the strong or weak acid?

Answer 5

The weaker acid (higher pKa).

Question 6

How is the relative acidity of uncharged acids related to the structure of their conjugate bases?

Answer 6

If A- is very stable, then HA must be a strong acid. If A- is very unstable, then HA must be a weak acid.

Question 7

How can the acidity of two uncharged acids be compared?

Answer 7

Compare the stability of their anionic conjugate bases.

Question 8

What does the A in ARIO represent?

Answer 8

Atom. Which atom bears the charge? For elements in the same row of the periodic table, electronegativity is the dominant effect. For elements in the same column, size is the dominant effect.

Question 9

What does the R in ARIO represent?

Answer 9

Resonance. A negative charge is stabilized by resonance.

Question 10

What does the I in ARIO represent?

Answer 10

Induction. Electron-withdrawing groups, such as halogens, stabilize a nearby negative charge via induction.

Question 11

What does the O in ARIO represent?

Answer 11

Orbital. A negative charge in an sp-hybridized orbital will be closer to the nucleus and more stable than a negative charge in an sp3-hybridized orbital.

Question 12

How can the relative acidity of cationic acids (HA+ vs HB+) be assessed?

Answer 12

The stability of the cationic acids themselves can be compared.

Question 13

What does the equilibrium of an acid-base reaction favor?

Answer 13

Formation of the more stabilized charge.

Question 14

What is a Lewis acid?

Answer 14

An electron-pair acceptor

Question 15

What is a Lewis base?

Answer 15

An electron-pair donor

Question 16

What is CARIO used for?

Answer 16

CARIO is used to predict the strength of acids based on the stability of their conjugate base.

Question 17

What does the C in CARIO stand for?

Answer 17

Charge. Generally, uncharged molecules are more stable than charged molecules.

Question 18

How does the size of an atom affect its ability to stabilize a charge?

Answer 18

The larger the atom, the more stable a negative charge will be.

Question 19

How does the electronegativity affect an atom’s ability to stabilize a charge?

Answer 19

More electronegative atoms will better stabilize negative charges.