Molarity of pure water is \(\mathbf{5 5 . 5 5 .}\)
$$
\begin{aligned}
&\text { Molarity }=\frac{n}{\mathrm{~V}}=\frac{\text { Number of moles }}{\text { Volume }} \\
&\text { Number of moles }=\frac{\frac{\text { Mass }}{\text { Molar mass }}}{\text { Volume }} \\
&=\frac{1000}{18}=55.55
\end{aligned}
$$