Câu c.
$Mg^{0}$ `->`$Mg^{+2}$ `+2e` `| ×4`
$2N^{+5}$ `+8e->`$2N^{+1}$ `| ×1`
`=> 4Mg + 10HNO_3 -> 4Mg(NO_3)_2 + N_2O + 5H_2O`
Câu d .
$3Fe^{+8/3}$ `->`$3Fe^{+3}$ `+1e` ` | × 5x - 2y`
$xN^{+5}$ `+ ( 5x-2y)e-> `$xN^{2y/x}$ `| × 1 `
`=> ( 5x - 2y ) Fe_3O_4 +( 46x - 18y) HNO_3 -> ( 15x - 6 y )Fe(NO_3)_3 + N_xO_y + ( 23x - 9y ) H_2O`