Animated Solution for Chemistry - Salt Analysis: Consider the following reactions (unbalanced) $\text{Zn}+{\text{hot conc. H}}_2{\text{SO}}_4\to \text{G}+\text{R}+\text{X}$ $\text{Zn}+\text{conc. NaOH}\to \text{T}+\text{Q}$ $\text{G}+{\text{H}}_2\text{S}+{\text{NH}}_4\text{OH}\to \text{Z (a precipitate)}+\text{X}+\text{Y}$ Choose the correct option(s).

Imagine you are a detective in a chemistry lab, and you are handed three mysterious, unbalanced reactions. Your mission is to identify the unknown compounds and evaluate four statements about them. Let's break down this puzzle step by step.

The first reaction involves zinc reacting with hot, concentrated sulfuric acid:

Recall that concentrated sulfuric acid is a strong oxidizing agent. Instead of simply displacing hydrogen gas, it oxidizes the zinc and gets reduced to sulfur dioxide. This tells us that the products $\text{G}$, $\text{R}$, and $\text{X}$ are ${\text{ZnSO}}_4$, ${\text{SO}}_2$, and ${\text{H}}_2\text{O}$, though we don't know the exact order yet.

Moving to the second reaction, we see zinc reacting with concentrated sodium hydroxide:

Zinc is an amphoteric metal, meaning it can react with both strong acids and strong bases. When it reacts with a strong base like $\text{NaOH}$, it forms sodium zincate (${\text{Na}}_2{\text{ZnO}}_2$) and releases hydrogen gas. Thus, the products $\text{T}$ and $\text{Q}$ are ${\text{Na}}_2{\text{ZnO}}_2$ and ${\text{H}}_2$.

The third reaction is the key to unlocking the exact identities of our unknowns. It is a classic qualitative analysis test for Group IV cations:

When hydrogen sulfide is passed through a solution containing zinc ions in a basic medium (provided by ${\text{NH}}_4\text{OH}$), a precipitate of zinc sulfide ($\text{ZnS}$) is formed.

Comparing this with the given equation $\text{G}+{\text{H}}_2\text{S}+{\text{NH}}_4\text{OH}\to \text{Z}\downarrow +\text{X}+\text{Y}$, we can definitively say: - $\text{G}$ is ${\text{ZnSO}}_4$ - $\text{Z}$ is $\text{ZnS}$ - $\text{X}$ is ${\text{H}}_2\text{O}$ - $\text{Y}$ is $({\text{NH}}_4{)}_2{\text{SO}}_4$

Since $\text{X}$ is water, we can look back at the first reaction and conclude that $\text{R}$ must be ${\text{SO}}_2$.

Now that we have unmasked all the compounds, let's evaluate the given options.

Option A: The oxidation state of zinc in $\text{T}$ (${\text{Na}}_2{\text{ZnO}}_2$). Let the oxidation state of zinc be $x$.

The oxidation state is $+2$, not $+1$. So, Option A is incorrect.

Option B: The bond order of $\text{Q}$ (${\text{H}}_2$). A hydrogen molecule consists of two hydrogen atoms sharing a single pair of electrons, forming a single covalent bond. Therefore, its bond order is 1. Option B is correct.

Option C: The color of $\text{Z}$ ($\text{ZnS}$). In qualitative salt analysis, zinc sulfide is famous for being a dirty white precipitate. Option C is correct.

Option D: The shape of $\text{R}$ (${\text{SO}}_2$). The central sulfur atom in sulfur dioxide has six valence electrons. It forms two double bonds with the oxygen atoms, leaving one lone pair. According to VSEPR theory, this $s{p}^2$ hybridization with one lone pair results in a V-shaped or bent molecular geometry. Option D is correct.

In conclusion, the correct statements are B, C, and D. This problem beautifully connects the concepts of redox reactions, amphoterism, and qualitative salt analysis!