One mole of ${\mathrm{PCL}}_5$ is heated in a closed $2 {\mathrm{dm}}^3$ vessel. At equilibrium $40\% {\mathrm{PCl}}_5$ is dissociated. Calculate the equilibrium constant

Which of the following equations give ionic product of water?

(i) ${\mathrm{NH}}_{3\left(\mathrm{aq}\right)}+{\mathrm{H}}_2\mathrm{O}\leftrightarrows {\mathrm{NH}}_{4\left(\mathrm{aq}\right)}^{+}+{\mathrm{OH}}_{\left(\mathrm{aq}\right)}^{-}$

(ii) ${\mathrm{NH}}_{4\left(\mathrm{aq}\right)}^{+}+{\mathrm{H}}_2\mathrm{O}\leftrightarrows {\mathrm{H}}_3{\mathrm{O}}^{+}+{\mathrm{NH}}_{3\left(\mathrm{aq}\right)}$

(iii) ${\mathrm{NH}}_{2\left(\mathrm{aq}\right)}^{-}+{\mathrm{H}}_2\mathrm{O}\leftrightarrows {\mathrm{NH}}_{3\left(\mathrm{aq}\right)}+{\mathrm{OH}}^{-}$

(iv) ${\mathrm{NH}}_{3\left(\mathrm{aq}\right)}+{\mathrm{OH}}_{\left(\mathrm{aq}\right)}^{-}\leftrightarrows {\mathrm{NH}}_{2\left(\mathrm{aq}\right)}^{-}+{\mathrm{H}}_2\mathrm{O}$