\textbf{229-} If the pH of a weak acid HA solution is $2.5 \times 10^{-7}$ mol per milliliter, and 5 mol of it exists, what is the percent ionic dissociation of HA under experimental conditions?
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\hspace{2cm} (1) $0/f$ \hspace{3cm} (2) $0/Y$ \hspace{3cm} (3) $f$ \hspace{3cm} (4) $Y$
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