- [Maximum mark: 7]
The pH scale is a measure of the acidity of a solution. Its value is given by the formula
pH = −log₁₀[H⁺],
where [H⁺] is the concentration of hydrogen ions in the solution (measured in moles per litre).
(a) Calculate the pH value if the concentration of hydrogen ions is 0.0003. [2]
The pH of milk is 6.6.
(b) Calculate the concentration of hydrogen ions in milk. [2]
The strength of an acid is measured by its concentration of hydrogen ions. A lemon has a pH value of 2 and a tomato has a pH value of 4.5.
(c) Calculate how many times stronger the acid in a lemon is when compared to the acid in a tomato. [3]