Chemical and Ionic Equilibrium 2 Question 29
29. A certain weak acid has a dissociation constant of $1.0 \times 10^{-4}$. The equilibrium constant for its reaction with a strong base is
$(1984,1 \mathrm{M})$
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Solution:
- The reaction of $\mathrm{H} A$ with strong base is
$\mathrm{H} A+\mathrm{OH}^{-} \rightleftharpoons \mathrm{H}_{2} \mathrm{O}+A^{-}$
$$ K=\frac{\left[A^{-}\right]}{[\mathrm{H} A]\left[\mathrm{OH}^{-}\right]} \times \frac{\left[\mathrm{H}^{+}\right]}{\left[\mathrm{H}^{+}\right]}=\frac{K_{a}}{K_{w}}=\frac{10^{-4}}{10^{-14}}=10^{10} $$
