1.1 g of sample of copper ore is dissolved and Cu^(2+) (aq) is treated with KI the iodine thus liberated requried 12.12 cm^(3) of 0.1 M Na_(2)S_(2)O_(3) solution for tritration what is the percentage of copper in the ore ?

1.1 g of sample of copper ore is dissolved and Cu^(2+) (aq) is treated

1.	1.1 g of sample of copper ore is dissolved and Cu^(2+) (aq) is treated with KI the iodine thus liberated requried 12.12 cm^(3) of 0.1 M Na_(2)S_(2)O_(3) solution for tritration what is the percentage of copper in the ore ?
Answer» Solution :The complete balanced equation for the redox reaction is `2cu^(2+)+4I^(-)+2S_(2)O_(3)_^(2)rarrCu_(2)I_(2)+S_(2)O_(6)^(2-)+2I^(-)` No of MOLES of `S_(2)O_(3)^(2-)`used =`(12.12)/(1000)xx0.1=1.212xx10^(-3)` moles From the BALANCE equation 2 moles of `S_(2)O_(3)^(2-)` reduce `Cu^(2+)` =2 moles `therefore 1.212 xx10^(-3)` moles of `S_(2)O_(3)^(2-)` will reduce `Cu^(2+)=1.212 xx10^(-3)` moles Thus % AGE of Cu in the are =`(0.77)/(1.1)xx100=7%`