1) $C_{x}$$H_{y}$ +$H_{2}$$SO_{4}$ → $SO_{2}$ + $CO_{2}$ + $H_{2}$O 2) $Fe_{x}$$O_{y}$ + $H_{2}$$SO_{4}$ → $Fe(NO_{3})$$_{3}$ +S + $H_{2}$O 3) M + $HNO_{3}$ → $M(NO_{3})$$_{n}$ +NO + $H_{2}$0 4) $M_{x}$$O_{y}$ + $HNO_{3}$ → $M(NO_{3})$$_{n}$ +NO + $H_{2}$0 5) $Fe_{x}$$O_{y}$ + $O_{2}$ → $Fe_{n}$$O_{m}$

1 )CH4

2) Fe2O3

3)M??NO3)

4)Mg hay Mn ạ

5)Fe2O3 -Fe2O3

1.

xC-y/x ->xC+4 + (4x+y)e  .2

S+6 +2e ->S+4                 .(4x+y)

${\mathrm{2C}}_x$$H_y$ +(4x+y)$H_2$$S{O}_4$ → (4x+y)$S{O}_2$ +2x $C{O}_2$ +(4x+2y) $H_2$O

2.

xFe-2y/x ->xFe+3 +(3x+2y)e .6

S+6 +6e ->S                           .(3x+2y)

$F{e}_x$$O_y$ + (3x+2y)$H_2$$S{O}_4$ →6x $Fe\left(N{O}_3\right)$${}_3$ +(3x+2y)S + (3x+2y)$H_2$O

3.

M->Mn+ +ne     .3

N+5 +3e->N+2  .n

3M + 4n$HN{O}_3$ → 3$M\left(N{O}_3\right)$${}_n$ +nNO + 2n$H_2$0

4.

xM-2y/x ->xM+n +(nx+2y)e .3

N+5 +3e->N+2                    .(nx+2y)

${\mathrm{3M}}_x$$O_y$ + (4nx+2y)$HN{O}_3$ →3x $M\left(N{O}_3\right)$${}_n$ +(nx+2y)NO + (2nx+y)$H_2$0

5.

nxFe-2y/x ->nxFe-2m/n +(2ny-2nm) .2

O2+4e->2O2-                                    .(ny-nm)

${}_{\mathrm{2nFexFexOyOy\; +\; (ny-nm)O2O2\; \to \; 2xFenFenOmOm}}$