Question

Suppose you have a solution that might contain any or all of the following cations: Cu 2, Ag , Ba 2, and Mn2 . The addition of HBr causes a precipitate to form. After the precipitate is filtered off, H2SO4 is added to the supernate, and another precipitate forms. This precipitate is filtered off, and a solution of NaOH is added to the supernatant liquid until it is strongly alkaline. No precipitate is formed. Which ions are present in each of the precipitates

Answer 1

Ag⁺, Ba²⁺,

Step-by-step explanation:

We can solve this question using the solubility rules:

When an Halide as Br- is added to a solution, the ions that can be precipitate are Ag⁺, Hg₂²⁺ and Pb²⁺.

That means the first ion present is Ag⁺

When sulfates, SO₄²⁻ are added, the ions that precipitates are: Ag⁺, Ca²⁺, Sr²⁺, Ba²⁺, Hg₂²⁺ and Pb²⁺

The second ion present is Ba²⁺

Hydroxides of Cu²⁺ and Mn²⁺ are insolubles but as no precipitate are formed when the solution is strongly alkaline those ions are not present.