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Calculate the concentration of hypo (Na_(2)S_(2)O_(3)5 H_(2)O)solution in g dm^(-3) uf 10.0 ML of this solution decolourised 15 mL of (M)/(40) iodine solution |
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Answer» SOLUTION :The balanced equation for the REDOX reaction is `2S_(2)O_(3)^(2-)+I_(2) rarr2 I^(-)+S_(4)O_(6)^(2-)` From the balanced equation it is evident that 2 moles of `Na_(2)S_(2)O_(3)=1 "mole of" I_(2)` applying molarity equation we have `(M_(1)V_(1))/(n_(1))(Na_(2)S_(2)O_(3))=(M_(2)V_(2))/(n_(2))(I_(2)) or (M_(1)xx10)/(2)=(15xx1)/(1xx40) or M_(1)=(15xx1xx2)/(10xx40)=3/40` THUS the molarity of hte hypo solution `=3//40` M Mol MASS of `Na_(2)S_(2)O_(3)5 H_(2)O=248 g "mol"^(-1)` `therefore` Concentration of `Na_(2)S_(2)O_(3)5H_(2)O=(248xx3)/(40)=18.6 dx^(-3)` |
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