(1)

`3 xx |`$\mathop{Mg}\limits^{0}$ `->` $\mathop{Mg}\limits^{+2}$ `+2e`

`1 xx |`$\mathop{S}\limits^{+6}+6e$ `->` $\mathop{S}\limits^{ 0}$

`3Mg + 4H_2SO_4 -> 3MgSO_4 + S + 4H_2O`

(2)

`1xx |` $\mathop{P}\limits^{0}$ `->` $\mathop{P}\limits^{+5}$ `+ 5e`

`5 xx|` $\mathop{N}\limits^{+5}+e$ `->` $\mathop{N}\limits^{+4}$

`P + 5HNO_3 -> H_3PO_4 + 5NO_2 + H_2O`

(3)

`8xx |`$\mathop{Al}\limits^{0}$ `->` $\mathop{Al}\limits^{+3}$ `+3e`

`3xx |`$\mathop{N}\limits^{+5}+ 8e$ `->` $\mathop{N}\limits^{-3}$

`8Al + 30HNO_3 -> 8Al(NO_3)_3 + 3NH_4NO_3 + 9H_2O`

(4)

`1 xx|`$\mathop{S}\limits^{+4}$ `->` $\mathop{S}\limits^{+6}$ `+2e`

`1xx|`$\mathop{Br_2}\limits^{0}+2e$ `->` $\mathop{2Br}\limits^{-1}$

`SO_2 + Br_2 + 2H_2O -> H_2SO_4 + 2HBr`

(5)

`3xx |`$\mathop{3Fe}\limits^{+\dfrac{8}{3}}$ `->` $\mathop{3Fe}\limits^{+3}+1e$

`1xx |`$\mathop{N}\limits^{+5}+3e$ `->` $\mathop{N}\limits^{+2}$

`3Fe_3O_4 + 28HNO_3 -> 9Fe(NO_3)_3 + NO + 14H_2O`

(6)

`8 xx |`$\mathop{Al}\limits^{0}$ `->` $\mathop{Al}\limits^{+3}$ `+3e`

`3 xx|`$\mathop{S}\limits^{+6} + 8e$ `->` $\mathop{S}\limits^{-2}$

`8Al + 15H_2SO_4 -> 4Al(NO_3)_3 + 3H_2S + 12H_2O`