Final answer:
Gravimetric analysis is not suitable for determining trace amounts of ions because accurate mass measurements become difficult at low concentrations, and any impurities or handling losses can lead to significant errors.
Step-by-step explanation:
The question pertains to why gravimetric analysis is not suitable for determining trace amounts of ions. One of the key reasons gravimetric analysis is less effective for tracing small quantities of ions is due to its reliance on the mass measurement of the analyte, which can become increasingly difficult and inaccurate at low concentrations. This method requires the isolated analyte to be of a sufficient mass to be accurately weighed, which may not be achievable with trace amounts. Additionally, any impurities or handling losses will have a proportionally larger impact on the results for trace analyses, which can lead to significant errors in the final calculation of the analyte concentration. Therefore, more sensitive techniques like spectrophotometry or mass spectrometry are generally preferred for the analysis of trace ions.