\(Fe^{+\dfrac{2y}{x}}_x-\left(3x-2y\right)e\rightarrow xFe^{+3}\) x 1
\(N^{+5}+e\rightarrow N^{+4}\) ........................x ( 3x - 2y )
\(Fe_xO_y+\left(6x-2y\right)HNO_3\rightarrow xFe\left(NO_3\right)_3+\left(3x-2y\right)NO_2+\left(3x-y\right)H_2O\)