Midterm 3: Acids and Bases

Question 1

What is the Cirtic Acid structure formula?

Answer 1

Question 2

What is Malic acid structure formula?

Answer 2

Question 3

What are bases and acids behaviours in response to H+ and OH - in aqueous solutions?

Answer 3

Acids increase in hydrogen in H20, bases also increase in OH- in H2O

Question 4

How many interactions of H-Bonds are in H9O4+

Answer 4

The core structure contains three primary hydrogen bonds due to 𝐻3𝑂 + H3O + interacting with water.

Question 5

H20 generally donates a proton and becomes what?

Answer 5

OH-

Question 6

What is the relationship between acids and bases in H2O?

Answer 6

Acids must have a hydrogen to give away while bases must have a lone pair of electrons for acids to react with

Question 7

What is the conjugate base of water?

Answer 7

OH- when water is the acid in the reaction and X- of Hx

Example: H3O+ is conjugate acid of H2O

Question 8

Hydrogen sulphite is amphiprotic: What is the equation when its an acid? What is the equation when it acts as a base?

Answer 8

Question 9

For lewis acid and bases, what is required for a substance to be a proton acceptor?

Answer 9

Must have a pair of electrons. Lewis acids are electron pair acceptors and lewis bases are electron pair donors.

Question 10

What are examples of lewis acids?

Answer 10

H+ and CO2. CO2 is special because it is a molecule with multiple bonds but it behaves as a lewis acid

Question 11

Are metal ions acidic or basic?

Answer 11

Acidic. Metal ions attract unshared molecules.

Question 12

What occurs when your throw a metal ion in water?

Answer 12

Metal ion acts as the lewis acid and H2O acts as the base.

Electron density goes away from oxygen in water. this causes the hydrogen bond of water to become more polarized.

Question 13

What is the relationship between bases and acids?

Answer 13

Acids are proton donors and bases are proton acceptors.

A very weak acid will have a strong conjugate base

A very weak base will have a strong conjugate acid.

Question 14

What are the three rules regarding acid strength?

Answer 14

1. Strong acids completely transfer their protons to H2O and so their conjugate have no tendency to be protonated in H2O
2. Weak acids partially dissociate in H2O so they exist as a mixture of molecules and ions
3. Those with no acidity are substances like CH4 but those conjugate bases are strong (forms OH-)

Question 15

Answer 15

Question 16

How does H2O work in the presence of an acid and a base?

Answer 16

In the presence of acid H2O is a proton acceptor (H3O+) but in the presence of a base, it donates a proton (H2O-)

Question 17

What is Kw at 25 degree’s celcius?

Answer 17

Kw = 1.0 x 10 ^ -14

Question 18

What is H+ at room temperature with an OH- 0.010 M

Answer 18

Question 19

Freshly squeezed apple juice has a pH of 3.76. What is the concentration of H+?

Answer 19

Question 20

In acid and bases, the strength of acid depends on?

Answer 20

1. Polarity of the bond, a molecule with H will transfer a proton only if H-X bond is polarized.
2. Strength of the bond
3. Stability of the conjugate bases “X-“ the greater the stability, and the stronger the acid

Question 21

If the temperature increases in water, what is the effect to the pH?

Answer 21

The pH will decrease as heat increases, as does H+

Question 22

What occurs when electron density goes to “Y”

Answer 22

OH bonds become weaker and more polar, therefore a loss of H+ acid will occur.

This happens because the conjugate base is the anion and stability of base increases.

Question 23

What is the relationship between electronegativity and acid?

Answer 23

Strength of the acid increases as additional electronegative atoms are attached to the central atoms

Question 24

Is perchloric acid stronger than HOCl?

Answer 24

Perchloric acid (HClO₄) is significantly stronger than hypochlorous acid (HOCl) due to its very low pKa, high oxidation state of chlorine, and resonance stabilization of the conjugate base.

Question 25

Whats the pH of 0.040M solution of HClO4?

Answer 25

So, a 0.040 M HClO₄ solution has a pH of approximately 1.40.

Question 26

0.30 M NaOH is 0.30 M NA+ and 0.30M OH-, What is the pH of a 0.0011 M solution of Ca(OH)2?

Answer 26

0.0011 M Ca(OH)₂ solution has a pH of approximately 11.34.

Question 27

Are most acids strong or weak acids?

Answer 27

Most acids are weak acids. this means its not easy to find equilibrium because they don't completely disassociate. They only partially ionize in solution, we use Keq constant to expresses the extent of ionisation.

Question 28

What is the Ka of 0.10 M of formic acid with a pH of 2.38 at 25 degrees celcius?

Answer 28

K a =1.8 × 10^−4

Question 29

In a weak acid problem what will the exponent generally be?

Answer 29

The exponent will generally be between X^-3 and X^-10

Question 30

Anything that has a lone pair of nitrogen electons is generally what?

Answer 30

A weak base

Question 31

What are the two classes of bases?

Answer 31

1. Contains neutral species with non-bonding pair of electrons serve as proton acceptor 2. Anions of weak acids

Question 32

What is the simplest organic amine?

Answer 32

CH4NH2 - Methylamine