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Free iodine is titrated against standard reducing agent usuallywith sodium thiosulphate , i.e. K_(2)Cr_(2)O_(7) + 6Kl + 7H_(2)SO_(4) to Cr_(2)(SO_(4))_(3) + 4K_(2) SO_(4) + 7H_(2)O+l_(2) 2CuSO_(4) + 4Kl to Cu_(2)l_(2) + 2K_(2)SO_(4) + l_(2) l_(2) + Na_(2)S_(2)O_(3) to 2Nal + Na_(2)S_(4)O_(6) In iodometric titration, starch solution is used as an indicator. Starch solution gives blue or violet colour with free iodine .At the end point , blue or violet colour disappears when iodine is completely changed to iodide. What volume of 0.40 M Na_(2)S_(2)O_(3) would be required toreact with l_(2) liberated by adding 0.04 mole of Kl to 50 ml of 0.20 M CuSO_(4) solution ? |
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Answer» `12.5` ML |
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