For the reaction $C{H}_{4\left(g\right)}+2O_{2\left(g\right)}\iff C{O}_{2\left(g\right)}+2H_2{O}_l$:
($\Delta H=-170.8kJmo{l}^{-1}$). Which of the following statement is not true?

For the reaction, $C{H}_4\left(g\right)2O_2\left(g\right)\iff C{O}_2\left(g\right)+2H_{2}O\left(I\right)$
$\Delta H_r)=-170.8kJmo{l}^{-}$
This equilibrium is an example of haterogenous chemical equilibrium. Hence for it.
$\frac{\left[C{O}_2\right]}{\left[C{H}_4\right]{\left[O_2\right]}^2}$ ....(ii)
(equilibrium constant on the basis of concentration) and
$K_p=\frac{P_{c{o}_2}}{p_{ch{.}_4}\times p_{o_2^2}}$ (ii)
(equilibrium constant according to partial pressure)
Thus, in this contentration of $C{O}_2\left(g\right)\text{and}{H}_{2}O\left(I\right)$ are not equal at equilibrium
The equilibrium constant $K_p=\frac{\left[C{O}_2\right]}{\left[C{H}_4\right]\left[O_2\right]}$ is not correct expression.
On adding $C{H}_4$ (g) or $O_2$ (g) at equilibrium $K_c$ will be decreased according to expression (i) but $K_c$ remains constant at constant temperature for a reaction. Hence, on addition of $C{H}_4$ or$O_2$ equilibrium will cause to the right.
Combustan reaction is an example of exothermic reaction.