Question

Calculate the concentration of each of the ions in the following solutions of strong electrolytes: (a) 0.085 M HNO3 (b) 0.170 M [Fe(H2O)6]2 (SO4)3

Answer 1

a) HNO3 is a strong electrolyte hence get completely dissociated in the solvent

Hence

HNO3 gives H+ and NO3-

1Moles of HNO3 gives 1 mole of H+ and 1 mole of NO3-

Hence the Molarity will not change for each electrolyte.

Hence gives you 0.085 molar of H+ and 0.085 molar of NO3-

b) [Fe(H2O)6]2 (SO4)3

[Fe(H2O)6]2 (SO4)3 is a strong electrolyte hence get completely dissociated in the solvent

Hence

[Fe(H2O)6]2 (SO4)3 gives 2 x [Fe(H2O)6]+ and 3 x (SO4)-

1Moles of [Fe(H2O)6]2 (SO4)3 gives 2 moles of [Fe(H2O)6+] and 3 moles of (SO4)-

Hence the Molarity will be change for each electrolyte.

Hence gives you 0.170 x 2= 0.34 molar of [Fe(H2O)6+ and 3 x 0.17=0.51 molar of (SO4)-