Question

What is the function of sodium thiosulphate (0.025N) and why do we need to add in the solution until it turn into pale yellow colour?What is the function of sodium thiosulphate (0.025N) and why do we need to add in the solution until it turn into pale yellow colour?

Answer 1

Explanation:

hydroxide forming a mixture of higher, oxides (brown colour compound), which on acidification in the presence of an iodide, release iodine in a quantity chemically equivalent to the oxygen content of the water sample.

The liberated iodine is then titrated with a standard solution of sodium thiosulphate.

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