A salt with few drops of conc. HCl gives apple green colour in flame test. The group precipitate of the salt is dissolved in acetic acid and treated with $\mathrm{K}_2 \mathrm{CrO}_4$ to give yellow precipitate. When the sodium carbonate extract of the salt solution is heated with conc. $\mathrm{HNO}_3$ and ammonium molybdate, it resulted a canary yellow precipitate. The cation and anion present in the salt are respectively,
Select the correct option:
A
$\mathrm{Ca}^{2+}$ and $\mathrm{SO}_4^{2-}$
B
$\mathrm{Ba}^{2+}$ and $\mathrm{PO}_4^{3-}$
C
$\mathrm{Mn}^{2+}$ and $\mathrm{PO}_4^{3-}$
D
$\mathrm{Ba}^{2+}$ and $\mathrm{SO}_4^{2-}$
✓ Correct! Well done.
✗ Incorrect. Try again or view the solution.
Solution
(i) $\mathrm{Ba}^{+2}$ gives apple green colour while $\mathrm{Ca}^{+2}$ and $\mathrm{Sr}^{+2}$ gives brick red and crimson red respectively in flame test.
(ii) $\mathrm{Ba}^{+2}+\mathrm{CrO}_4^{2-} \rightarrow \mathrm{BaCrO}_4$
Yellow ppt
(iii) $\begin{array}{r}\mathrm{PO}_4^{3-}+\text { Conc } \mathrm{HNO}_3+\left(\mathrm{NH}_4\right)_2 \mathrm{MoO}_4 \\ \left(\mathrm{NH}_4\right)_3\left[\mathrm{P}\left(\mathrm{Mo}_3 \mathrm{O}_{10}\right)_4\right] \\ \text { Canery yellow ppt }\end{array}$
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