A reagent which gives brilliant red precipitate with Nickel ions in basic medium is

Core Logic

In qualitative inorganic analysis, both Ba²⁺$Ba^{2+}$ and Ca²⁺$Ca^{2+}$ belong to Group V cations. To identify Ba²⁺$Ba^{2+}$ & Ca²⁺$Ca^{2+}$, the group reagent (NH₄)₂CO₃ + NH₄Cl$(NH_{4})_{2}CO_{3} + NH_{4}Cl$ (with NH₄OH$NH_4OH$) is used. As a result, they precipitate out as insoluble carbonates: BaCO₃$BaCO_{3}$ & CaCO₃$CaCO_{3}$.

Pattern Recognition

Group V cations (Ba²⁺$Ba^{2+}$, Sr²⁺$Sr^{2+}$, Ca²⁺$Ca^{2+}$) always precipitate as Carbonates upon adding (NH₄)₂CO₃$(NH_4)_2CO_3$ in an ammoniacal medium.

Chapter Mix

Class 11 Chemistry: Salt Analysis

Related Formula

Core Logic

• Treating an ammonium salt (containing NH₄^+$\mathrm{NH}_4^+$) with NaOH$\mathrm{NaOH}$ releases Ammonia gas (X = NH₃$\mathrm{X} = \mathrm{NH}_3$):

• Passing ammonia gas through Nessler's reagent (Y = K₂[HgI₄] + KOH$\mathrm{Y} = \mathrm{K}_2[\mathrm{HgI}_4] + \mathrm{KOH}$) produces a distinct brown precipitate (known as iodide of Millon's base):

Hence, X$\mathrm{X}$ is NH₃$\mathrm{NH}_3$ and Y$\mathrm{Y}$ is K₂HgI₄ + KOH$\mathrm{K}_2\mathrm{HgI}_4 + \mathrm{KOH}$.

Pattern Recognition

Classic confirmatory test for ammonium ion: heating with alkaline solutions yields NH₃$\mathrm{NH}_3$ gas, which always produces a brown precipitate with alkaline Nessler's reagent.

Chapter Mix

Class 11 Chemistry: Qualitative Salt Analysis Class 12 Chemistry: p-Block Elements

Related Formula

Core Logic

Nessler's reagent (K₂[HgI₄]$\text{K}_2[\text{HgI}_4]$ in alkaline solution) reacts explicitly with ammonia gas (NH₃$\text{NH}_3$) or ammonium ions to create an insoluble iodide of Millon's base (HgO (NH₂)I$\text{HgO}\cdot\text{Hg}(\text{NH}_2)\text{I}$). This characteristic complex showcases a signature brown structural coloration.

Step 1: Finalization

Thus, the unknown tracking gas 'X' is uniquely identified as ammonia (NH₃$\text{NH}_3$).

Pattern Recognition

Ammonia detection relies directly upon alkaline potassium tetraiodomercurate(II) resulting in brown Millon's base precipitations.

Chapter Mix

Class 12 Chemistry: Principles of Qualitative Analysis

Related Formula

Core Logic

When a salt containing sulphide is warmed with dilute H₂SO₄$H_2SO_4$, H₂S$H_2S$ gas is evolved. H₂S$H_2S$ gas turns lead acetate paper black due to the formation of lead sulphide (PbS$PbS$), not lead sulphite. Thus, Statement I is correct, but Statement II is incorrect.

Pattern Recognition

Lead acetate paper test is standard for H₂S$H_2S$ gas, forming black PbS$PbS$. Always watch out for the trap suffix: sulphite (SO₃²⁻$SO_3^{2-}$) vs sulphide (S²⁻$S^{2-}$).

Chapter Mix

Class 11 Chemistry: Qualitative Analysis Class 11 Chemistry: p-Block Elements