Which test is used for detecting lead residues?

The sodium rhodizonate test is specifically designed for the detection of lead residues. This test involves the application of sodium rhodizonate, which reacts with lead to form a colored complex. When lead residues are present, they will turn a distinct red color upon application of the test reagent. This color change is indicative of lead presence and is particularly useful in forensic contexts for analyzing gunshot residues or other scenarios where lead might be present.

The other tests mentioned are utilized for different substances or have different applications. The acetic acid test is not specific to lead but is used in other contexts. The thiocyanate test is associated with the detection of certain metal ions. Barium analysis is focused on detecting barium rather than lead. Thus, the usage of sodium rhodizonate in detecting lead residues makes it the most appropriate choice in this context.