Question

Addition of solution of oxalate to an aqueous solution of mixture of $B{a^{2 + }},\,S{r^{2 + }}\,\& \,C{a^{2 + }}$ will precipitate:
(A) $C{a^{2 + }}$
(B) $C{a^{2 + }}\,\& \,S{r^{2 + }}$
(C) $B{a^{2 + }}\,\& \,S{r^{2 + }}$
(D) All of these

Answer 1

Hint: When an aqueous solution containing a mixture of $B{a^{2 + }},\,S{r^{2 + }}\,\& \,C{a^{2 + }}$ is added, what will precipitate? is the question that we have to answer. All three of the aforementioned ions— $B{a^{2 + }},\,S{r^{2 + }}\,\& \,C{a^{2 + }}$ —have insoluble oxalates in water. Thus, the answer would be all of these.

Complete Step by Step Solution:
First of all let us first know what is meant by an aqueous solution. An aqueous solution is the one in which water serves as the solvent. In chemical equations, it is often represented by adding to the appropriate chemical formula. For instance, $N{a^ + } + C{l^ - }$ might be used to depict a solution of table salt, or sodium chloride, in water.

Also, we know that Precipitation is the process of changing a dissolved substance from a supersaturated solution to an insoluble solid in an aqueous solution. Precipitate refers to the produced solid.

We see that all the elements of the mixture given in the question are from group number 2.
The oxalate of the three metals listed in the question— $C{a^{2 + }},\,S{r^{2 + }},\,B{a^{2 + }}$ —is insoluble in water.

The fifth group's precipitate solution in acetic acid results in a white precipitate that contains ammonium oxalate solution.
For example: ${\left( {C{H_3}COO} \right)_2}Ca + {\left( {N{H_4}} \right)_2}{C_2}{O_4}\, \to \,{\left( {COO} \right)_2}Ca + 2C{H_3}COON{H_4}$
From the whole theory given above we can conclude that all the given ions, namely, $C{a^{2 + }},\,S{r^{2 + }},\,B{a^{2 + }}$ will precipitate when solution of oxalate is added to an aqueous solution of mixture of $B{a^{2 + }},\,S{r^{2 + }}\,\& \,C{a^{2 + }}$ .
Hence, D. is the correct option.

Note: Kindly note that to decide whether some element is soluble in a given solution or not, we use solubility principles. The exceptions included in these principles are as important as the laws themselves. More such questions can be made for various other elements and solvents.