The emf of the cell Pt | H2 (g, p) | HCI (aq, b) | Hg2Cl2 (s)

Question:

The emf of the cell Pt | H2 (g, pΘ) | HCI (aq, b) | Hg2Cl2 (s) | Hg (l) has been measured with high precision (G.]. Hills and D].G. Ives, J. Chem. Soc., 311
(1951)) with the following results at 25°C:
B/(mmolkg-1) 1.6077 3.0769 5.0403 7.6938 10.9474
E/V 0.60080 0.56825 0.54366 0.52267 0.50532
Determine the standard emf of the cell and the mean activity coefficient of HCI at these molalities. (Make a least-squares fit of the data to the best straight line.)