Solution:Concept- The creation of an insoluble salt is the subject of a precipitation process. We perform the reaction of two solutions that include soluble salts, and the result is this insoluble salt. The precipitate is the insoluble salt that emerges from the solution after this. Different ions may be present in the solution, which can be ascertained through precipitation reactions.
To determine which alternative doesn't precipitate, we shall test each one on the diluted HCl.
When , silver nitrate reacts with dilute HCl it gives white ppt.
When , lead nitrate reacts with dilute HCl it gives white ppt.
When , mercurous nitrate reacts with dilute HCl it gives a yellowish-white ppt.
When , cuprous nitrate reacts with dilute HCl it does not give any ppt.
Hence, the correct answer is option 4.