Question

The molality of an aqueous sodium nitrate solution is 2.81 m. What is the mole fraction of NaNO3? The molar mass of NaNO3 is 85.00 g/mol; the molar mass of water is 18.02 g/mol. 0.0506 0.239 0.00281 0.193 0.0482

Answer 1

molality of NaNO3   = 2.81m

2.81m NaNO3 solution means 2.81moles of NaNO3 dissolve in 1Kg (1000g) of water

no of moles of NaNO3 (n NaNO3) = 2.81 moles

no of moles of H2O (n H2O) = W/G.M.Wt

                                              = 1000/18.02 = 55.55moles

mole fraction of NaNO3    = n NaNO3/n NaNO3 + n H2O

                                          = 2.81/2.81+ 55.55

                                          = 2.81/58.36

                                           = 0.0482

0.0482 >>>>>answer