Question

A solution possibly contains K⁺, Pb²⁺, Ag⁺, Fe²⁺ and/or Ni²⁺. Which of the following statements is true about what could be concluded from the fact that the addition of HCl produces a precipitate?

O Ag is the only species present.


O Both Ag⁺ and Pb²⁺ are present and no other ions are present.


O Either Ag⁺. Pb²⁺ or both are present.This does not give us any information about the other three ions.


O Only K⁺, Fe²⁺ or Ni2t could be present in solution.

Answer 1

The formation of a precipitate after adding HCl to the solution suggests the presence of Pb²⁺ or Ag⁺ ions, as their chlorides are insoluble in water. K⁺, Fe²⁺, or Ni²⁺ cannot be confirmed with this specific test.

Step-by-step explanation:

The question is asking what can be inferred when a precipitate forms after adding HCl to a solution potentially containing K⁺, Pb²⁺, Ag⁺, Fe²⁺, and Ni²⁺. The formation of a precipitate upon the addition of HCl suggests the presence of insoluble chlorides. PbCl2, AgCl, and Hg₂Cl₂ are typically the chlorides that would precipitate from a solution when HCl is added as most metal chloride salts are soluble, except for these.

In the given set of cations, the observation of a precipitate implies the presence of either Pb²⁺ or Ag⁺ ions because the chlorides of these metals are not soluble in water. Therefore, it can be concluded that at least one of these ions is present in the solution. However, the presence of K⁺, Fe²⁺, or Ni²⁺ cannot be confirmed based on this test alone since their respective chloride salts are generally soluble in aqueous solutions.