U2-1-3 - Strong and Weak Acids

Question 1

Conjugate base

Answer 1

Species formed when an acid loses a proton (H⁺)

Question 2

Conjugate acid

Answer 2

Species formed when a base gains a proton (H⁺)

Question 3

Identify the conjugate acid

HCN(aq) + H₂O(ℓ) ⇌ CN⁻(aq) + H₃O⁺(aq)

Answer 3

H₃O⁺
(aq)

acid formed by base (H₂O) accepting a proton

Question 4

Identify the conjugate base

HCN(aq) + H₂O(ℓ) ⇌ CN⁻(aq) + H₃O^₊(aq)

Answer 4

CN⁻(aq)

base formed by acid (HCN) donating a proton

Question 5

Strong acid/base

Answer 5

Completely dissociates into ions in aqueous solution

Question 6

Weak acid/base

Answer 6

Only partially dissociates into ions in aqueous solution

Question 7

Examples of strong acids

Answer 7

HCl

H₂SO₄

HNO₃

Question 8

Examples of strong bases

Answer 8

Metal hydroxides

Question 9

Examples of weak acids

Answer 9

CH₃COOH (any organic acid)

H₂CO₃ (carbonic acid)

H₂SO₃ (sulfurous acid).

Question 10

Examples of weak bases

Answer 10

NH₃

amines (contain -NH₂ group)

Question 11

What is K_a?

Answer 11

Acid dissociation constant

Question 12

If K_a is low, the acid is …

Answer 12

weak

(only partially dissociates)

Question 13

If K_a is high, the acid is …

Answer 13

strong

(fully dissociates)

Question 14

For strong acids, pK_a is …

Answer 14

low.

Question 15

For weak acids, pK_a is …

Answer 15

high.

Question 16

Which will conduct electricity better:

a strong or weak acid solution?

Answer 16

Strong

(More ions in solution at same concentration)

Question 17

Which will have lower pH at the same concentration:

strong or weak acid?

Answer 17

Strong

(more H⁺ ions in solution)