Chapter 4.3: Acid Dissociation Constants, pKa, and the Relative Strengths of Acids and Bases

Question 1

If the pH of a buffered aqueous solution is higher than the acid pKa, will the acid be protonated or deprotonated?

Answer 1

For a given acid, it will be predominantly deprotonated if the pH of a buffered aqueous solution is higher than the acid pKa

Question 2

What is the formula for pKa?

Answer 2

pK_a = -log₁₀K_a

Question 3

Describe the relationship between pKa value and strength of acid

Answer 3

the larger the value of pKa, the weaker the acid o the smaller the value of pKa, the stronger the acid

Question 4

Describe the relationship between strength of acid and strength of conjugate base

Answer 4

the weaker the acid, the stronger its conjugate base o the stronger the acid, the weaker its conjugate base

Question 5

If the pH is lower than the pKa, will the acid be protonated or deprotonated?

Answer 5

If the pH is lower than the pKa, the acid will be predominantly protonated

Question 6

What is the acid dissociation constant?

Answer 6

K_a = K_eq[H₂O] = ([H₃O⁺][A^-])/[HA]