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pH Chart In our last post: Types, Preparation & Uses of Salts , we studied that salts are the products of the neutralization reactions between acids and bases. Following this fact, all salts are expected to have a neutral pH of 7 in solution. Interestingly, some salts produce solutions with pH > 7 (basic solutions), while others produce acidic solutions with pH < 7. Such salts, which are the products of either weak acids and strong bases or strong acids and weak bases, decompose in water to form two products. This phenomenon is known as hydrolysis. Recall that from our post on pH in Acids & Bases (Part III) , we learnt that water contains equal concentration of hydrogen and hydroxide ions. Therefore, the dissolution of a salt in water is likely to upset this ionic equilibrium based on the salt's composition. This is the underlying principle of hydrolysis of salts. So, in this post, we shall be looking at the hydrolysis of different types of salts based on th

p H & pH Scale The pH (hydrogen ions potential) is a measure of the acidity or alkalinity of a solution. The concept of pH was introduced by Sörensén in 1909 to bring about the convenience of working with very dilute solutions. To this effect, he developed a scale consisting of fifteen numbers (0 - 14), which is used in pH meter, for measuring the relative acidity or alkalinity in solutions. This scale is known as the pH scale. The numbers in the pH scale are the values of the negative logarithms of the hydrogen ions concentrations in such solutions. From the above, we can define pH as the negative logarithm of the hydrogen ions concentration [H+] to base 10. Mathematically, this is given as: pH = - log [H+] ..........................(i) Alternatively, the above equation can be expressed as pH = log 1/[H+] .........................(ii) From equation (ii), we can also define pH as the logarithm of the reciprocal of the hydrogen ions concentration to base 10. The pH