# 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?

May 15, 2017

$p H$ should be GREATER than $7$.........Why?

#### Explanation:

At the equivalence point, we have a solution that is stoichiometric in $N a N {O}_{2} \left(a q\right)$. Now $N {O}_{2}^{-}$ 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 $p H$ out quantitatively if we had the concentration of $N a N {O}_{2}$ and $p {K}_{a}$ for $\text{nitrous acid}$. Given that $H {O}^{-} > {10}^{-} 7 \cdot m o l \cdot {L}^{-} 1$, $p H > 7$, 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.