Estimate the mean ionic activity coefficient
a) CaCl2 in an aqueous solution that is 0.01 mol/kg CaCl2 and 0.03 mol/kg NaF
b) NaCl in an aqueous solution that is 0.02 mol/kg NaCl and 0.035 mol/kg Ca(NO3)2.
Assume that the Debye-Hückel limiting law for the activity coefficients applies in this situation.