Chapter 4.4: The Position of Equilibrium in Acid-Base Reactions

Question 1

What does a positive pKa indicate about the dissociation of the acid?

Answer 1

a positive value indicates that most acid molecules remain undissociated in water

Question 2

What does a negative pKa indicate about the dissociation of the acid?

Answer 2

• A negative pKa value indicates that the majority of molecules of the acid are dissolved in water

Question 3

If the majority of molecules of an acid are ubdissociated in water, is the pKa positive or negative?

Answer 3

positive

Question 4

If the majority of molecules of an acid are dissociated in water, is the pKa positive or negative?

Answer 4

negative

Question 5

What side of the reaction does the position of equilibrium always favor in an acid-base reaction?

Answer 5

• In an acid-base reaction, the position of equilibrium always favors reaction of the stronger acid and stronger base to form the weaker acid and weaker base
o Thus at equilibrium the major species present are the weaker acid and weaker base