Question

Lead nitrate has a water solubility of 56.5 g/cm3 at 20 °C. What lead concentration is this in molar? What nitrate concentration is this in molar?

Answer 1

Solubility of lead nitrate Pb(NO3)2 = 56.5 g/cm3

Lead nitrate contains 1 mol of cation Pb+2 and 2 mol of anions NO3-

Molar Lead concentration

= solubility/molecular weight of Pb+2

= (56.5 g/cm3)/(207.2g/mol)

= 0.2726 mol/cm3 x 1000 cm3/L

= 272.6 mol/L

Molar nitrate concentration

= solubility/molecular weight of NO3-

= (56.5 g/cm3)/(2*62g/mol)

= 0.4556 mol/cm3 x 1000 cm3/L

= 455.6 mol/L