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♤ The pH scale is a measure of how acidic or basic (alkaline) a solution is.
♤ It ranges from 0 to 14. A pH of 7 is neutral.
♤ A pH less than 7 is acidic, and a pH greater than 7 is basic.
♤ It was devised in 1909 and it is a logarithmic index for the hydrogen ion concentration in an aqueous solution.
♤ pH values decreases as hydrogen ion levels increases.
♤ A solution with pH 4 is ten times more acidic than solution with pH 5, and a hundred times more acidic than solution with pH 6.
♤ Whilst the pH range is usually given as 0 to 14, lower and higher values are theoretically possible.