Nitrogen dioxide $(N{O}_2)$ exists in equilibrium with its dimer $(N_2{O}_4)$ according to

$2N{O}_2{N}_2{O}_4$

This reaction has an equilibrium constant $K_{eq}$ of $6\mathrm{.}15{10}^{-6}pp{m}^{-1}$ at $298K.$ If the total concentration of $N{O}_2+N_2{O}_4$ in a power plant plume is measured to be $4000ppm,$ what is the actual concentration of $N{O}_2$ in the plume?

$3.$ You are monitoring air quality for your city and around noontime you measure $N{O}_2$ and $NO$ concentration of $50$ and $5ppb,$ respectively. Neglecting hydrocarbons and assuming the concentrations of $N{O}_2$ and $NO$ are controlled by:

$N{O}_2+hvNO+O$

$O+O_2{O}_3$

$NO+O_{3}N{O}_2+O_2$

where the reaction rate $k_a=0\mathrm{.}0027s^{-1}$ and $k_c=1\mathrm{.}53{10}^{-14}c{m}^{3}molecul{e}^{-1}{s}^{-1}.$ From this, please estimate the steady$-$state concentration of ozone $($in ppb$).$ Keep two significant figures in the answer. The molar volume is $23\mathrm{.}6\frac{L}{m}ol.$