At 100⁰ C, the value of pK_w is

 $\text{Ionic product }\left({\text{K}}_{\mathrm{w}}\right)$$=product O{\text{H}}^{+}\text{ ions concentration and }{\text{ OH}}^{-}\text{ions } \text{ concentration}$ ${\text{K}}_{\text{w}}=\left[{\text{H}}^{+}\right]\times \left[{\text{OH}}^{-}\right]$ 

 $\text{Where } \text{ Kw is the equilibrium constant.}$ $\text{It is also called the dissociation constant or the ionization constant of water.}$

${\text{p}}^{{\text{K}}_{\text{w}}}$$={\text{p}}^{\text{H}}{\text{ + p}}^{\text{OH}}$

For pH, it will be less than 14 and for pOH, it will be greater than 14. Therefore, at 100⁰ C, the value of p^Kw is 14.