How many moles of \( \mathrm{NaF}(\mathrm{s}) \) should be added to 1.0 L of \( 0.10 \mathrm{M} \mathrm{HF}(\mathrm{aq}) \) to make a buffer at \( \mathrm{pH}=3.50 \) ? Assume no volume change. whifh two components?
two weak acids
a strong acid and a strong base
a weak acid and its conjugate base
a strong acid and a salt