It is claimed that the following reactions are taking place in a reactor:

$4N{H}_3+5O_{2}6H_{2}O+4NO$

$4N{H}_3+7O_{2}6H_{2}O+4N{O}_2$

$O_2+2NO2N{O}_2$

$2N{O}_2{N}_2+2O_2$

$4N{H}_3+3O_{2}6H_{2}O+2N_2$

$2NO{N}_2+O_2$

a$)$ How many of these reactions are independent? Write down an independent set of reactions.

b$)$ Select an appropriate set of independent rates and write down the relations for the reaction rates of other species in terms of selected independent rates.