Question

What is The pH and pOH of a 1.00x10-3M solution of CH3COOH (Ka=1.75x10-5) ?

Answer 1

pH = 3.9

pOH = 10.1

Step-by-step explanation:

Since
`CH _ 3COOH` is a weak acid to find the pH of
`CH _ 3COOH` we use the formula

`pH = - (1)/(2) log(Ka) - (1)/(2) log(c)`

where

Ka is the acid dissociation constant

c is the concentration

From the question

Ka of
`CH _ 3COOH` = 1.75 × 10^-5

c = 1.00 × 10-³M

Substitute the values into the above formula and solve for the pH

That's

`pH = (1)/(2) ( - log(1.75 * {10 }^( - 5) - log(1.00 * {10}^( - 3) ) ) \\ = (1)/(2) (4.757 + 3) \\ = (1)/(2) * 7.757) \\ = 3.8785 \: \: \: \: \: \: \: \:`

We have the answer as

pH = 3.9

To find the pOH we use the formula

pH + pOH = 14

pOH = 14 - pH

pOH = 14 - 3.9

We have the answer as

pOH = 10.1

Hope this helps you