Final answer:
The question involves a buffer solution composed of I- and HIO and the calculation of pH before and after the addition of HCl. The Henderson-Hasselbalch equation is used for these calculations, but the pKa of HIO is required for exact values. Without the pKa, the method can be described, but actual pH values cannot be provided.
Step-by-step explanation:
The question asks to determine the pH of a buffer solution containing I- and HIO, and to calculate the pH change when a certain amount of HCl is added to this buffer. To find the initial pH of the buffer, we would need to use the Henderson-Hasselbalch equation, which is pH = pKa + log([A-]/[HA]) where [A-] is the concentration of the conjugate base (I-) and [HA] is the concentration of the weak acid (HIO). Unfortunately, without the pKa value for HIO, we cannot calculate the pH directly from the information given.
For part (c), once we know the initial pH and the amounts of HCl and the buffer, we can calculate the moles of HCl added and the new concentrations of HIO and I-, then use the Henderson-Hasselbalch equation again to find the new pH after the addition of HCl. Note: The provided problem does not include enough information to solve it directly. Specifically, the pKa of HIO is required for a full calculation. Without this information, we can describe the method but not provide a definitive answer.