Question

To a solution of acetic acid, solid sodium acetate is added gradually. When $x$ mole of salt is added, the $pH$ has a certain value. If $y$ mole of salt is added, the $pH$ this time changes by $0.6$ units to previous $pH$. What is the ratio of $x$ and $y$? If the solution is diluted after addition of $y$ mole salt, $pH$ of solution finally increases. Given that $y>x$. If true enter 1, if false enter 0.

Answer 1

As you know, acetic acid, $C{H}_{3}COOH$ is a weak acid, which means that it does not dissociate completely in aqueous solutionn to form hydronium actions, $H_3{O}^{+}$ and acetate anions, $C{H}_{3}CO{O}^{-}$.

${C{H}_{3}COOH}_{\left(aq\right)}+{H_{2}O}_{\left(l\right)}\rightleftharpoons {C{H}_{3}CO{O}^{-}}_{\left(aq\right)}+H_3{O^{+}}_{\left(aq\right)}$

Sodium acetate, $C{H}_{3}COONa$ a soluble ionic compound, is the salt of acetate anion.

${C{H}_{3}COONa}_{\left(aq\right)}\rightleftharpoons {C{H}_{3}CO{O}^{-}}_{\left(aq\right)}+{{Na}^{+}}_{\left(aq\right)}$

So, when you are adding sodium acetate to a solution of acetic acid, concentration of acetate anions increases. Thus, there will be a decrease of hydronium ions resulting in pH increase.