Academic Experts Solutions for Chapter: Qualitative Analysis, Exercise 2: KVPY PROBLEMS (PREVIOUS YEARS)

An organic compound fused with metallic sodium dissolves in water and the solution is divided into two parts. One part is treated with ${\mathrm{FeSO}}_4$, boiled and filtered. In the filtrate addition of ${\mathrm{FeCl}}_3$ does not produce any precipitate. To the other part, addition of sodium nitro prusside produces violet colour. The organic compound contains.

Oxalic acid when treated with potassium permanganate in the presence of an acid, produces

When $\mathrm{Co}\left(\mathrm{II}\right)$ chloride is dissolved in concentrated $\mathrm{HCl}$ a blue solution is obtained. Upon dilution with water. The color changes to pink because

Aqueous solution of metallic nitrate $\mathrm{X}$ reacts with ${\mathrm{NH}}_4\mathrm{OH}$ to form $\mathrm{Y}$, which dissolves in excess ${\mathrm{NH}}_4\mathrm{OH}$. The resulting complex is reduced by acetaldehyde to deposit the metal. $\mathrm{X}$ and $\mathrm{Y}$, respectively are:

When ${\mathrm{H}}_2\mathrm{S}$ gas is passed through a hot acidic aqueous solution containing ${\mathrm{Al}}^{3+}, {\mathrm{Cu}}^{2+}, {\mathrm{Pb}}^{2+}$ and ${\mathrm{Ni}}^{2+}$, a precipitate is formed which consists of:

A metal $\left(\mathrm{X}\right)$ dissolves both in dilute $\mathrm{HCl}$ and dilute $\mathrm{NaOH}$ to liberate ${\mathrm{H}}_2$. Addition of ${\mathrm{NH}}_4\mathrm{Cl}$ and excess ${\mathrm{NH}}_4\mathrm{OH}$ to an $\mathrm{HCl}$ solution of $\mathrm{X}$ produces $\mathrm{Y}$ as a precipitate. $\mathrm{Y}$ is also produced by adding ${\mathrm{NH}}_4\mathrm{Cl}$ to the $\mathrm{NaOH}$ solution of $\mathrm{X}$. The species $\mathrm{X}$ and $\mathrm{Y}$, respectively, are:

When heated in air, brown copper powder turns black. This black powder would then turn brown again when heated with:

A filter paper, when soaked in salt $\mathrm{X}$, turns brown when exposed to ${\mathrm{HNO}}_3$ vapour. The salt $\mathrm{X}$ is: