Question

How does pH of an acid change with dilution?

Answer 1

the pH is used to determine the strength of acid or a base. It is the negative logarithm of hydrogen ion concentration. pH scale is used to determine the acidity and basicity of the aqueous solution. Its value ranges from $0$ to $14$.

Complete step by step answer:
Dilution is defined as the process in which concentration is decreased by adding water or any other solvent in the solution.
As we know that, the acid solution contains more number of hydrogen ions and the basic solution contains more number of hydroxide ions. The addition of water in an acidic and basic solution results in change in its pH.
When water or any other solvent is added in an acid, then the concentration of hydrogen ion decreases. This results in an increase of the ph of acid towards $7$. This means that ph increases on diluting the acid solution.
The ph of a highly concentrated acid is around $1 - 2$ but as we add water or any other solvent the pH increases towards $7$. When it is highly diluted and a very little amount of acid is present in the solution then the pH becomes $7$.

Note: Dilution is defined as a process of reducing concentration of a solute in the solution. For that we need to add more solvent without the addition of more solute.
If the pH value is less than $7$, then it is considered as an acidic solution.
If the pH value is more than $7$, then it is considered as a basic solution.
If the pH value is equal to $7$, then it is considered a neutral solution.