Question

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

Answer 1

`"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 `HF` bond, and the polarizing power of the `F^-` ion.

`HF(aq) + NaOH(aq) rightleftharpoons NaF(aq) +H_2O(aq)`

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

`F^(-) + H_2O rightleftharpoons HF(aq) + HO^-`

The presence of small quantities of hydroxide ion would bump up `pH` above `7` at equilibrium.