At 600K, 2mol of NO are mixed with 1mol of O _ 2 . 2 NO _ (g) + O _...

$2NO + {O}_{2} \to 2NO$

$\begin{cases}2 & 1 & - \\ 2 - 2x & 1 - x & 2x \\ 1 . 2 & 0 . 6 & 0 . 8\end{cases}$

Total number of moles=$2 . 6$

According to Dalton's law,

Partial pressure=Total pressure$\times$Mole fraction

Mole fraction$= \dfrac{Numberofmolesofonecomponent}{Totalnumberofmoles}$

${K}_{P} = \dfrac{{P}^{2}{NO}_{2}}{{P}^{2}NO . {P}_{{O}_{2}}}$

=$\dfrac{{\left(\dfrac{0 . 8}{2 . 6} \times 1\right)}^{2}}{{\left(\dfrac{1 . 2}{2 . 6} \times 1\right)}^{2}\left(\dfrac{0 . 6}{2 . 6} \times 1\right)}== \dfrac{1 . 664}{0 . 864} = 1 . 8824 ≃ 2$