Calculating The Ph Of A Weak Acid

Question 1

How to calculate the ph of a weak acid

Answer 1

First write the ka expression

Ka =. [H+]^2
—————
HA

Rearrange the expression to calculate [H+]2

Calculate [H+] by taking the square root

Calculate pH
pH = -log10

Question 2

Calculating the concentration of a weak acid

Answer 2

Calculate [H+] using

[H+] =10-pH

Write down Ka expression

Rearrange equation to find [HA]