AP Chemistry: Acids & Bases 3

Question 1

The acid dissociation constant Ka of a weak acid is 1.0 × 10^-5. What is its pKa?

Accepted Answer

5

Answer

pKa = -log(Ka) = -log(1.0 × 10^-5) = 5.

Question 2

Which of these is the strongest acid based on Ka values?

Accepted Answer

Ka = 6.3 × 10^-3

Answer

A larger Ka means greater dissociation, so 6.3 × 10^-3 is the strongest acid.

Question 3

What salt is produced when HCl reacts with NaOH?

Accepted Answer

NaCl

Answer

Neutralization of HCl with NaOH produces NaCl and water.

Question 4

An aqueous solution of NH4Cl is expected to be:

Accepted Answer

Acidic

Answer

The ammonium ion (NH4+) hydrolyzes to release H+, making the solution acidic.

Question 5

In the Lewis theory, an acid is a substance that:

Accepted Answer

Accepts an electron pair

Answer

A Lewis acid is an electron-pair acceptor.

AP Practice Test