The Ph Of A Solution

1881 Words May 5th, 2015 8 Pages
The pH of a solution is a measure of the hydrogen ion concentration in the solution. It can be defined as the negative log of the hydrogen ion concentration. pH = - log [H+]
When the pH of a solution is below 7, it is an acidic solution. This means that there is a higher concentration of free H+ ions in the solution. When the pH of a solution is above 7, it is a basic solution and it means that there is a higher concentration of OH- ions in the solution. This is because the bases tend to lose their electrons and bond with protons. So When the pH = 7, the solution is neutral. In other words, the acidity of the solution decreases with higher pH values. The pH values of the solution can be calculated by different methods. The oldest method of testing the pH of solutions is the Litmus paper. Litmus paper is a paper that is a blend of natural dyes, which are acquired from lichens. It turns red in acidic conditions and blue in basic conditions. There are different types of indicators that determine the pH range of the solutions and produce different colors corresponding to their acidic and basic mediums. Following is a table that displays the color change of the different indicators and their respective pH ranges.

Indicator pH range Color Change
Methyl Red 4.2 -6.3 Red - Yellow
Litmus Paper 4.5 – 8.3 Red - Blue
Phenol Red 6.8 – 8.4…
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