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An impure sample of `As_(2)O_(3)` weighitng `20 gm` was dissolved in water containing `10 gm` of `NaHCO_(3)` and the final solution was diluted to `400ml`.`20ml` of this solution was oxidised by `25ml` of a solution of `l_(2)`. Another solution of hypo containing `1.24 gm` of `Na_(2)S_(2)O_(3).5H_(2)O` in `40ml` was used to exactly reduce `25 ml` of same `l_(2)` solution (impurities inert) calculate `%` fo `AS_(2)O_(3)` in the sample (at. wt. of `As=75`) |
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Answer» Correct Answer - `00049.50` `00049.50` `M_("hypo")=(1.24xx1000)/(248xx40)=0.125` meq of hypo`=` meq of `I_(2)` in `25 ml =0.125xx1xx40=5` meq of `l_(2)=` meq of `As_(2)O_(3)=5` meq of `AS_(2)O_(3)` in `20 ml` solution `=5` so meq of `AS_(2)O_(3)` in `400 ml=(5xx400)/20=100` mole of `AS_(2)O_(3)=0.05xx198=9.9g` wt. % `=9.9/20xx100=49.5%` |
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