What is pH ?
Acidity is a
rather familiar concept because many foods and drinks are acidic in
varying degrees: vinegar, lemon juice, tomatoes, citrus fruits etc..
acidic solutions there are basic solutions. It is difficult for us to
understand what is a basic solution because food and beverages are
almost never basic. There are basic solutions among cleaning products
like bleach or detergents.
The pH is a
number that indicates whether a solution is acidic or basic and with
The pH is a chemical variables that have no unity.
How to measure pH ?
The pH can
be measured using pH paper:
It consists of strips soaked with chemicals that take different colors
depending on pH.
A drop of solution must be placed on a strip. Comparing its color to a
color index, we can deduce the pH value.
pH paper gives only an approximate value of the pH to the nearest unit.
The pH of a
solution can be measured using a device called a pH meter.
It consists of a probe (itself consists of electrodes). Once this probe
is immersed in a solution, the pH meter shows the pH value.
The pH meter provides a quick and accurate measurement (usually to the
pH of acidic and basic solutions
- If the pH
is between 0 and 7 then the solution is acidic.
The lower the pH is, the more acidic the solution is
- If the pH is between 7 and 14 then the solution is basic.
The higher the pH is, the more basic the solution is
- If the pH is 7 then the solution is neither acid nor basic, it is
said to be neutral