The percentage of copper in copper (II) salt can be determined by using a thisulphate titration. A `0.305g` of copper (II) salt was dissolved in water and added to an excess of potassium iodide solution liberating iodine according to the following equation:
`2Cu^(2+)(aq)+4I^(-)(aq)to2Cul(s)+I_(2)(aq)` The iodine liberated required `24.5cm^(3)` of a 0.1 mole `dm^(-3)`solution of sodium thiosulphate for titration according to reaction:
`2S_(2)O_(3)^(2-)+I_(2)(aq)+S_(4)O_(6)^(2-)(aq)`
The percentage of copper by mass in the copper (II) salt is (Atomic mass of copper =63.5)

Options

A. 64.2
B. 51
C. 48.4
D. 25.5

Answer

b