After reading this article you will learn about:- 1. Numerical Properties of Chlorine 2. Hydrolysis of Chlorine 3. Role in Disinfecting Water.
Numerical Properties of Chlorine:
Some numerical properties of chlorine are given below:
It has a strong oxidizing activity because atoms have a strong tendency to acquire an extra electron to complete an octet.
The oxidation potential of chlorine systems at 25°C are given below:
Hydrolysis of Chlorine:
Chlorine is known to hydrolyse in water to yield HOCl, H+ and Cl–. Besides these, CI+ and Cl3– and OCl– ions have also been detected under different conditions.
Cl2 + H2O ⇋ HOCl + H+ + Cl– … (1)
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HOCl + H+ ⇋ H2OCl+ … (2)
Cl2 + Cl– ⇋ Cl3– … (3)
HOCl ⇋ H+ + OCl– … (4)
According to Dr. Kudesia, molecular chlorine is the principal oxidizing agent. It destroys the protoplasm of micro-organisms.
Role of Chlorine in Disinfecting Water:
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For routine disinfections of drinking and waste water generally chlorine is used being both efficient and cheap. The chlorine compounds are useful and economical. Chlorine was first used in Municipal Water Supply in 1908 in America.
It is most effective in checking pathogenic micro-organisms. The chlorine reacts with water to form hypochlorous acid and nascent oxygen. Both of these are powerful germicides. The excess of chlorine is removed by sulphites called antichlor.
A Swedish chemist K.S. Scheele discovered chlorine in 1876. It has seven electrons in the outer shell and is the second member of the seventh column of periodic table.
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It is a greenish-yellow gas having pungent odour. If it is inhaled in small quantity, it may cause headache. If inhaled in large quantity, it may prove fatal. It dissolves in water yielding chlorine water. Below 0°C chlorine forms crystals of hydrate Cl2.6H2O and Cl28H2O.