Question

In the mineral, barium ions can be identified by:
A.Green colour in ame
B.Yellow precipitate $Cr{O_4}^{2 - }$ solution
C.White precipitate with $S{O_4}^{2 - }$
D.All of the above

Answer 1

We must remember that the barium ions can be identified by precipitation of its salt. For the purpose of definition, minerals are specifically defined as naturally occurring inorganic substances which are found in solid state which have a well-defined chemical structure, formula, and crystal structures. Different minerals vary in their physical properties, that is colour, density, size etc…

Complete step by step answer:
In the given question we have to identify the correct option how barium ions can be identified.
As we know that barium can be as barium sulphate, barium chromate, etc...

Option A: The colour of the barium is also green in appearance. The characteristics emission spectra are used to differentiate between the elements. In the emission spectra wavelength corresponding to green colour is observed for barium. So, the barium gives off a green colour.
Therefore, the option A is correct.

option B: Potassium chromate taken to perform the reactions is of white colour in the powered sort. Now, we write the chemical reaction formed by the reaction of potassium chromate with the solute of barium sulphate,
${K_2}Cr{O_4} + BaS{O_4} \to {K_2}S{O_4} + BaCr{O_4}$
In this reaction,$K_{_2}^{}S{O_4}$ is potassium sulphate and $BaCr{O_4}$ is barium chromate which gives yellow precipitate.
Therefore, the option B is correct.

option C: The white precipitate of barium sulphate is formed by the reaction between $S{O_4}^{2 - }$ and $B{a^{2 + }}$. The other product formed is sodium chloride which will remain dissolved in the solution. The reaction that occurs in this case where there is an exchange of ions between reactants is called double displacement reaction.
$N{a_2}S{O_4} + BaC{l_2} \to BaS{O_4} + 2NaCl$
In this reaction $BaS{O_4}$gives white colour precipitate.
Therefore, this option is correct.

So, the correct answer is Option D.

Note:
We must remember that the barium ions of its insoluble yellow $BaCr{O_4}$ salt, if $C{a^{2 + }}$ is present they will also precipitate in the presence of high concentrations of $Cr{O^{2 - }}_4$. In barium sulphate, the valence of barium and sulphate ion is +2 and -2 respectively. Barium sulphate is harmless for humans because it’s not toxic and can be used medically.