Question

Cation of salt A when treated in flame gives apple green colour. When salt A is heated with Chromate solution gives yellow precipitate & when salt is heated with conc $HNO_3$ & Ammionium molybdate it gives canary yellow ppt. Salt A contains :

• A. $Ba^{+2}$ and $PO_4^{3-}$
• B. $Ca^{+2}$ and $SO_4^{2-}$
• C. $Ba^{+2}$ and $SO_4^{2-}$
• D. $Sr^{+2}$ and $PO_4^{3-}$

Answer 1

The Correct Option is A

Identification of ions via specific dry and wet chemical tests.

ANALYSIS:
1. Apple green flame $\to$ Presence of Barium ($Ba^{2+}$).
2. Reaction with Chromate $\to$ Formation of Yellow Barium Chromate ($BaCrO_4$). This supports the cation identification.
3. Ammonium molybdate test with $HNO_3$ $\to$ Formation of Canary yellow ammonium phosphomolybdate precipitate. This is diagnostic for Phosphate ($PO_4^{3-}$).
4. Combining results: Cation is $Ba^{2+}$, Anion is $PO_4^{3-}$. Matches Option (1).