Question

A 100 mL sample of solution containing the cobalt ion is titrated with 0.015 M EDTA consuming 25.3 mL. Enter the solute concentration in ppm (mg / vol).

Answer 1

Using the following relation we can know the concentration of Cobalt ion:

V1*C1=V2*C2

Where

V1= 100ml

V2= 25.3 ml

C2= 0,015M

We substitute the values and clear C1 from the relation and calculating:

C1=(V2*C2)/V1

C1= (25,3 ml*0,015M)/100 ml

C1= 3,795*10^-3 M

Now we can make a conversion of this concentration remembering that M= miles/liters of solution, so we convert the cobalt ion moles to milligrams for get ppm concentration that is mg/liters of solution:

PPM= (3,795*10^-3 moles/liter)*(58.93 g/mol)*(1000mg/g)

PPM= 223.63 mg/l

Answer: the solute concentration of cobalt ion is 223.63 mg/l