Question

Are the following solutions acidic, basic, ot neutral.

1. [H3O+] = 2.5 x 10-9 M

2. [OH-] = 1.6 x 10 -2 M

3. [H3O+] = 7.9 x 10-3 M

Answer 1

1) Basic

2) Basic

3) Acidic

Step-by-step explanation:

pH of a solution is a measure of the H3O+ ions in the solution and hence reflects its acidity.

`pH = -log[H3O+]`

Solutions are classified as acidic, basic or neutral based on the pH range

-pH < 7, acidic

- pH = 7, neutral

- pH > 7, basic

1) [H3O+] = 2.5*10^-9M

`pH = -log[H3O+]=-log[2.5*10^(-9)]=8.60`

Since pH > 7, solution is basic

2)[OH-] = 1.6*10^-2M

`pOH = -log[OH-]=-log[1.6*10^(-2)]=1.80`

pH = 14 - pOH = 14 - 1.80 =12.2

Since pH > 7, solution is basic

3) [H3O+] = 7.9*10^-3M

`pH = -log[H3O+]=-log[7.9*10^(-3)]=2.10`

Since pH < 7, solution is acidic