0.5 g sample of copper ore is converted into `CuSO_4` solution. The resulting solution is acidified with dilute `CH_3COOH` (acetic acid) and excess KI added. The liberated `I_2` required 0.248 g `Na_2S_2O_3.5H_2O` for complete reaction. Calculate the percantage of Cu in the ore.

A mixture containing As_(2)O_(3) and As_(2)O_(3) requried 20 " mL of " 0.05 N I_(2) for titration. The resulting solution is then acidified and excess KI was added. The liberated I_(2) required 1.24 g hypo (Na_(2)S_(2)O_(3).H_(2)O) for complete reaction. Calculate the mass of the mixture. The reactions are As_(2)O_(3)+2I_(2)+2H_(2)OtoAs_(2)O_(3)+4H^(o+)+4I^(ɵ) As_(2)O_(5)+4H^(o+)+4I^(ɵ)toAs_(2)O_(3)+2I_(2)+2H_(2)O

638.0 g of CuSO_(4) solution is titrated with excess of 0.2 M KI solution. The liberated I_(2) required 400 " mL of " 1.0 M Na_(2)S_(2)O_(3) for complete reaction. The percentage purity of CuSO_(4) in the sample is

638.0 g of CuSO_(4) solution is titrated with excess of 0.2 M KI solution. The liberated I_(2) required 400 " mL of " 1.0 M Na_(2)S_(2)O_(3) for complete reaction. The percentage purity of CuSO_(4) in the sample is