Q.70. A salt with few drops of conc. HCl gives apple green colour in flame test. The group precipita

Q: What is the correct answer for this exam Chemistry Q70?

The correct answer is B. Sol. Let's break down the observations to identify the cation and anion. **Cation identification:** 1. "A salt with few drops of conc. HCl gives apple green colour in flame test." This is a characteristic test for Ba²⁺ ions. Ca²⁺ gives brick red, and Sr²⁺ gives crimson red. So, the cation is Ba²⁺. 2. "The group precipitate of the salt is dissolved in acetic acid and treated with K₂CrO₄ to g

Q: Q.70. 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 K₂CrO₄ to give yellow precipitate. When…

The correct answer is B. Sol. Let's break down the observations to identify the cation and anion. **Cation identification:** 1. "A salt with few drops of conc. HCl gives apple green colour in flame test." This is a characteristic test for Ba²⁺ ions. Ca²⁺ gives brick red, and Sr²⁺ gives crimson red. So, the cation is Ba²⁺. 2. "The group precipitate of the salt is dissolved in acetic acid and treated with K₂CrO₄ to g

Q: What are the options for this this exam Chemistry question?

A. Ca²⁺ and SO₄²⁻ · B. Ba²⁺ and PO₄³⁻ · C. Mn²⁺ and PO₄³⁻ · D. Ba²⁺ and SO₄²⁻

Question

Q.70. 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 K₂CrO₄ to give yellow precipitate. When the sodium carbonate extract of the salt solution is heated with conc. HNO₃ and ammonium molybdate, it resulted a canary yellow precipitate. The cation and anion present in the salt are respectively.

FirstInTest · Accepted Answer

Sol. Let's break down the observations to identify the cation and anion.

**Cation identification:**
1.  "A salt with few drops of conc. HCl gives apple green colour in flame test."
    This is a characteristic test for Ba²⁺ ions. Ca²⁺ gives brick red, and Sr²⁺ gives crimson red. So, the cation is Ba²⁺.
2.  "The group precipitate of the salt is dissolved in acetic acid and treated with K₂CrO₄ to give yellow precipitate."
    Ba²⁺ ions react with K₂CrO₄ (potassium chromate) to form a yellow precipitate of Barium Chromate (BaCrO₄), which is soluble in acetic acid. This confirms Ba²⁺.

**Anion identification:**
1.  "When the sodium carbonate extract of the salt solution is heated with conc. HNO₃ and ammonium molybdate, it resulted a canary yellow precipitate."
    This is the ammonium molybdate test for phosphate (PO₄³⁻) ions. Phosphate ions react with ammonium molybdate in the presence of nitric acid to form a canary yellow precipitate of ammonium phosphomolybdate, (NH₄)₃[P(Mo₃O₁₀)₄].
    So, the anion is PO₄³⁻.

Therefore, the cation is Ba²⁺ and the anion is PO₄³⁻.

Let's check the options:
(1) Ca²⁺ and SO₄²⁻
(2) Ba²⁺ and PO₄³⁻ - This matches our findings.
(3) Mn²⁺ and PO₄³⁻
(4) Ba²⁺ and SO₄²⁻

Answer

Ca²⁺ and SO₄²⁻

Answer

Ba²⁺ and PO₄³⁻

Answer

Mn²⁺ and PO₄³⁻

Answer

Ba²⁺ and SO₄²⁻

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