Calculate the equilibrium concentrations that result when $1\mathrm{.}00$ M HCl $($g$)$ and $0\mathrm{.}25$ M O$2($g$)$ react and come to equilibrium. $($All four reactants and products are gases and belong in the equilibrium expression.$)$ If you assume small x$,$ dont forget to test your assumption$\mathrm{.}4$ HCl$($g$)+$ O$2($g$)2$ Cl$2($g$)+2$ H$2$O$($g$)$ Kc $=3\mathrm{.}1\backslash$times $10^13$