When $150\mathrm{.}0$ mL of a weak base $($which can only accept a single proton$)$ were titrated with $0\mathrm{.}100$ M HCl$,30\mathrm{.}00$ mL were required to reach the equivalence point. The pH at the equivalence point was $4\mathrm{.}00.$ What was the pH when only $25\mathrm{.}00$ mL of HCl had been added?