Find the value of the dissociation constant of water $K$ (considered as an acid) at $25^oC$ :
a) $K $ $=$ $ [H_2O]$ $ =$ $ 55.5\;M$ b) $K$ $ =$ $ K_e$ $ =$ $ 1.0 \cdot 10^{-14}$ c) $K$ $ =$ $ K_e \cdot [H_2O]$ $ =$ $ 5.6 \cdot 10^{-13}$ d) $K$ $ =$ $ K_e / [H_2O]$ $ = $ $1.8 \cdot 10^{-16}$
d) is correct , $K$ $ = $ $\frac{K_e}{[H_2O]}$ $=$ $1.8\cdot 10^{-16}$