b
\(\begin{array}{l}
{\rm{M(N}}{{\rm{O}}_{\rm{3}}}{)_x}\,\, \to \,\,{M_2}{(S{O_4})_x}\\
\,\,\,\,\,\,\,\,\frac{1}{{E + 62}}\,\,\,\, = \,\,\,\frac{{0.86}}{{E + 48}}\,\,\,\,\,\,\,\,\,{E_{wSO_4^{ - 2}}} = \frac{{96}}{2} = 48\\
{E_{wNO_3^o}} = \frac{{62}}{1}
\end{array}\)