Question

Calculate the pH and pOH of the following solution and identify each solution as acidic, basic or neutral. (with solutions)

1. [H3O+] = 1.0 x 10-9 M

2. [OH-] = 1.0 x 10-8 M

3. [H3O+] = 0.0010 M

4. [OH-] = 0.010 M

Answer 1

In the question molarity of different solution is given

and we know that

$pH= -log[H_3O^+]$

$pOH= -log[OH^{-1}]$

1 . $pH= -log[1.0\times 10^{-9}]$

pH= 9

Since, its pH value is 9 so it is mild basic

2 . $pOH= -log[1.0\times 10^{-8}]=8$

pH = 14-8= 6

so it is weak acid

3 . $pH= -log[1.0\times 10^{-3}]=3$

It is acidic

4 . $pOH= -log[1.0\times 10^{-2}]= 2$

pH = 12 it is basic