Question

When `HNO_2` is titrated with `NaOH` to the equivalence point is the pH of the resulting solution greater than, less than or equal to seven?

Answer 1

`pH` should be GREATER than `7`.........Why?

Explanation:

At the equivalence point, we have a solution that is stoichiometric in `NaNO_2(aq)`. Now `NO_2^-` is the conjugate base of a fairly weak acid; in effect, this means that the conjugate base competes relatively strongly for the proton, and thus AT EQUIVALENCE, the following equilibrium occurs to some extent:

`""^(-)NO_2(aq) +H_2O rightleftharpoons HNO_2(aq) + HO^-`

We could work the `pH` out quantitatively if we had the concentration of `NaNO_2` and `pK_a` for `"nitrous acid"`. Given that `HO^(-)>10^-7*mol*L^-1`, `pH>7`, and a BASIC solution is specified.

If you are clear on what I have argued, well and good. If no, ask away and someone will help you.