# Acids and Bases Self-Assessment and Practice

Find the pH for a solution of Ca(OH)2 with a molarity of 1.0 x 10-4.

[H+][OH] = 1.0 x 10-14
[H+][2(1.0 x 10-4] = 1.0 x 10-14
[H+] = 5.0 x 10-11
pH = -log [H+]
pH = -log [5.0 x 10-11]
pH = 10

The letters “pH” represent the French words “pouvoir hydrogene” which means “hydrogen power”.

The definition of pH is pH is equal to the negative log (logarithm) of the _________ ion concentration of a solution.

hydrogen

The logarithm of a number is the power to which 10 must be raised to equal that number.

A pH value of less than 7 indicates a(n) ____________ solution.

acidic

A pH value of ________ indicates a neutral solution.

7

A pH value of more than 7 indicates a(n) _______________ solution.

basic

The greater the [H+] concentration, the ________ the pH.

lower

If a solution is _______________ the [H+] concentration equals the [OH] concentration.

neutral

An aqueous base has a pH of 8.1. Another has a pH of 10. Which solution has the larger concentration of [OH] ions?
a. The solution with a pH of 10 has a larger concentration of [OH] ions.
b. The solution with a pH of 8.1 has a larger concentration of [OH] ions.

A.

Determine the pH of a 0.035M H2SO4 solution.

pH = -log [H+] = -log [2(3.5 x 10-2] = -(-1.2) = 1.2

The pH of a 0.010M Mg(OH)2 solution is ______.

[H+][OH] = 1.0 x 10-14
[H+][2(1.0 x 10-2)] = 1.0 x 10-14
[H+] = 5.0 x 10-13
pH = -log [H+] = -log [5.0 x 10-13] = -(-12.3)
pH = 12

What is the hydrogen ion concentration of an aqueous HCl solution that has a pH of 3.0?

pH = -log [H+
3.0 = -log [H+]
[H+] = 1.0 x 10-3 M

What is the hydroxide ion concentration of this same solution?

[H+][OH] = 1.0 x 10-14
[1.0 x 10-3][OH] = 1.0 x 10-14
[OH] = 1.0 x 10-11 M

Which ion, H+ or OH, is in greater concentration?

H+
(1.0 x 10-3 is greater than 1.0 x 10-11)

Is this solution acidic or basic?