pH is a measure of the amount of activity of hydrogen ions (H+) in a solution and thus its alkalinity or acidity. Although a pH value is unitless, it is not a random scale; the number rises from a description grounded on the activity of hydrogen ions in the solution. pH is described as “the negative of the logarithm of the molar hydronium-ion concentration.”
pH Formula is arithmetically articulated as
The pH Formula can also be noted as
Solved numerical based on pH are provided under.
Problem 1: Calculate the pH of human arterial blood in which the hydronium ion concentration is 4.0 ×× 10-8M.
The concentration of hydronium ion is 4.0 × 10-8M
Thus, we can make use of the formula,
pH = – log[4.0 × 10-8]
pH = 7.40
As the hydronium ion concentration is provided till two decimal places we can note the pH with two significant figures.
Problem 2: A brand of carbonated beverage has a pH of 3.16. What is the hydronium ion concentration of the beverage?
The concentration of hydronium ion is
[H3O+] = antilog (-pH) = 10-pH
[H3O+] = antilog (-3.16) = 10-3.16
[H3O+] = 7.0 × 10-4M