A1.000 ml aliquot of a solution containing cu2+ and ni2+ is treated with 25.00 ml of a 0.04590 m edta solution. the solution is then back titrated with 0.02207 m zn2+ solution at a ph of 5. a volume of 21.73 ml of the zn2+ solution was needed to reach the xylenol orange end point. a 2.000 ml aliquot of the cu2+ and ni2+ solution is fed through an ion-exchange column that retains ni2+ . the cu2+ that passed through the column is treated with 25.00 ml of 0.04590 m edta . this solution required 24.47 ml of 0.02207 m zn2+ for back titration. the ni2+ extracted from the column was treated witn 25.00 ml of 0.04590 m edta . how many milliliters of 0.02207 m zn2+ is required for the back titration of the ni2+ solution?