Question

The concentration of zinc ion in blood serum is about 1000 ppb. Express this meq/L?

Answer 1

it is given that concentration of $Zn^{2+}$ ion in blood serum = 1000ppb
density of blood serum = 1.025 g/mL [it is given by experimental data ]
Let's take volume of solvent is 1L
then, mass of solvent = 1.025 × 1000 = 1025g

we know, ppb = mass of solute/mass of solution × 10^9

1000 = mass of solute/1025 × 10^9

mass of solute = 1025/10^6 = 1.025 × 10^-3 g

now, concentration in mole/L = mass of solute/molar mass of solute
= 1.025 × 10^-3/65.39 g/mol
= 0.01567 × 10^-3
= 1.567 × 10^-5 mol/L
now, concentration in millimole /L = 1.567 × 10^-2 millimole/L

we also know, normality = n - factor × molarity
here n - factor is 2
so, normality = 2 × 1.567 × 10^-2 meq/L
= 3.134 × 10^-2 meq/L