# What should the pH of salt water be?

Of aqueous sodium chloride? $p H = 7$.
Sodium chloride is the salt of a strong base, $N a O H$, and a strong acid, $H C l$. Because this is a strong base/strong acid pair, by definition, their counterions, $N {a}^{+}$, and $C {l}^{-}$, do not undergo water hydrolysis. Contrast this behaviour with an aqueous solution of $\text{sodium fluoride}$. The $p H$ of this solution is $> 7$. Given that $H F \left(a q\right)$, unlike $H C l , H B r , H I$, is a WEAK ACID, how can this solution behaviour be rationalized?