# In which solution would a pH>7 be measured: "A. Phosphoric acid;" "B. sodium fluoride;" "C. hydrogen chloride;" "D. sodium bromide."?

Aug 18, 2016

$\text{Option B}$

#### Explanation:

Let's use an example. say hydrogen fluoride, the which in water behaves as a moderately strong acid, due to (i) the strength of the $H F$ bond, and the polarizing power of the ${F}^{-}$ ion.

$H F \left(a q\right) + N a O H \left(a q\right) r i g h t \le f t h a r p \infty n s N a F \left(a q\right) + {H}_{2} O \left(a q\right)$

If such a neutralization occurred, the solution would be stoichiometric in sodium fluoride. This would be involved in water hydrolysis:

${F}^{-} + {H}_{2} O r i g h t \le f t h a r p \infty n s H F \left(a q\right) + H {O}^{-}$

The presence of small quantities of hydroxide ion would bump up $p H$ above $7$ at equilibrium.