Acids & Bases

Arrhenius

100

How does the Arrhenius theory define an acid?

any substance that, when in water, dissociates and increases the concentration of H₃O or H⁺.

200

How does the Arrhenius theory define a base?

any substance that, when in water, dissociates and increases the concentration of OH^-

300

Is HClO₄ an acid or base?

acid

400

HI is considered an acid because

A) it is a polar molecule.

B) it can dissolve in water.

C) it produces hydronium ions in solution.

D) it produces hydroxide ions in solution.

C) it produces hydronium ions in solution.

Brønsted–Lowry

100

How does the Brønsted–Lowry theory define an acid?

a proton donor

200

How does the Brønsted–Lowry theory define a base?

a proton acceptor

300

Is NH₃ an acid or base?

base

400

Consider the reaction below. Which of the following species represent a conjugate acid-base pair? HSO₃⁻(aq) + HNO₂(aq) ⇌ H₂SO₃(aq) + NO₂⁻(aq)

A) HNO₂, NO₂⁻

B) HNO₂, H₂SO₃

C) HSO₃⁻, NO₂⁻

D) HSO₃⁻, HNO₂

A) HNO₂, NO₂⁻

Lewis

100

How does the Lewis theory define an acid?

​electron pair acceptor​

200

How does the Lewis theory define a base?

electron pair donor

400

List the 7 strong acids and 8 strong bases.

Strong acids:

• HCl
• HNO₃
• H₂SO₄
• HBr
• HClO₃
• HI
• HClO₄

Strong Bases:

• LiOH
• NaOH
• KOH
• RbOH
• CsOH
• Ca(OH)₂
• Sr(OH)₂
• Ba(OH)₂

Dissociation Constants

100

The weak acid HY is much stronger than weak acid HX. Which one of the following statements is true?

A) Y⁻ is a stronger base than X⁻.

B) Y⁻ is a weaker base than X⁻.

C) Y⁻ and X⁻ will be bases of approximately the same strength.

B) Y⁻ is a weaker base than X⁻.

200

Which one of the following correctly shows the weak acid equilibrium for formic acid, HCOOH?

A) HCOOH(aq) + H₂O(l) ⇌ HCO(OH)₂⁻(aq) + H⁺(aq)

B) HCOOH(aq) ⇌ HCO⁺(aq) + OH⁻(aq)

C) HCOOH(aq) + H₂O(l) ⇌ HCOOH₂⁺(aq) + OH⁻(aq)

D) HCOOH(aq) + H₂O(l) ⇌ HCOO⁻(aq) + H₃O⁺(aq)

D) HCOOH(aq) + H₂O(l) ⇌ HCOO⁻(aq) + H₃O⁺(aq)

300

Which one of the following correctly shows the weak acid equilibrium for nitrous acid, HNO₂?

A) HNO₂(aq) ⇌ NO⁺(aq) + OH⁻(aq)

B) HNO₂(aq) + H₂O(l) ⇌ NO₂⁻(aq) + H₃O⁺(aq)

C) HNO₂(aq) + H₂O(l) ⇌ H₂NO₃⁻(aq) + H⁺(aq)

D) HNO₂(aq) + H₂O(l) ⇌ H₂NO₂⁺(aq) + OH⁻(aq)

B) HNO₂(aq) + H₂O(l) ⇌ NO₂⁻(aq) + H₃O⁺(aq)

400

The [H⁺] of a 0.10 M solution of cyanic acid (HCNO) is found to be 0.0010 M. Calculate the K_a, for cyanic acid.

K_a = 1.0 x 10^-5

500

Calculate the [OH^-] and the [H⁺] of a 0.0020 M solution of NaOH.

Hint: use the ion product constant

[OH^-]: 0.0020 M

[H⁺]: 5.0 x 10^-12 M

Misc.

100

List 5 properties of acids.

- electrolytes

- produce H⁺/H₃O in water

- sour taste

- litmus red

- neutralize bases

- proton donor

- electron pair acceptor

200

List 5 properties of bases.

- electrolytes

- produce OH^- in water

- bitter/chalky taste

- litmus blue

- feel soapy/slippery

- neutralize acids

- proton acceptor

- electron pair donor

300

What is the relationship between an acid/base and its conjugate?

Give one example of a conjugate acid-base pair.

Conjugate acid-base pairs are related by the loss or gain of H⁺. As acid strength increases, conjugate-base strength decreases.

Examples: 

- H₂SO₄ and HSO₄^-

- HNO₃ and NO₃^-

- H₃O⁺ and H₂O

400

What is an amphoteric substance?

a substance that can act as an acid or base (ex: H₂O, HCO₃^-)

500

What is a diprotic acid?

an acid (mostly weak) that has 2H⁺, which dissociate one at a time.