A dry food sample weighing 312.4 mg was digested to convert all the nitrogen into NH4*. The digestion solution was diluted to 1L. 20.00 ml of the diluted digestion solution were transferred to a 100 ml volumetric flask, 10 ml of 10.0 M NaOH were added, and the solution was made up to the mark with water. This final solution gave a reading of 339.3 mV. a) Plot (by hand or with software) a graph of E (mV) vs -log [NH4+ ] [5] b) Use this plot to determine the concentration of NH4 + in the final solution [3] c) Hence or otherwise, determine the %N (by mass) in the dry food [7]