Question

Consider the following reaction (unbalanced)

$$\begin{gathered} \mathrm{Zn}+{\mathrm{H}}_2{\mathrm{SO}}_4\to \mathrm{G}+\mathrm{R}+\mathrm{X} \\ (\mathrm{hot}\mathrm{conc}) \end{gathered}$$

$$\begin{gathered} \mathrm{Zn}+\mathrm{NaOH}\to \mathrm{T}+\mathrm{Q} \\ \left(\mathrm{conc}\right) \end{gathered}$$

$\mathrm{G}+{\mathrm{H}}_2\mathrm{S}+{\mathrm{NH}}_3\left(\mathrm{aq}\right)\to \mathrm{Z}+\mathrm{X}+\mathrm{Y}$

Choose the correct option(s)

• A. $\mathrm{R}$ is a $\mathrm{V}$-shaped molecule
• B. $\mathrm{Z}$ is dirty white in colour.
• C. Bond order of $\mathrm{Q}$ is $1$ in its ground state.
• D. The oxidation state of $\mathrm{Zn}$ in $\mathrm{T}$ is $+1$

Answer 1

Answer: (A), (B), (C)

Bond order of $\mathrm{Q}$ is $1$ in its ground state.

Explanation for correct options:

A. $\mathrm{R}$ is a $\mathrm{V}$-shaped molecule

1. The unknown reactants in reaction $$\begin{gathered} \mathrm{Zn}+{\mathrm{H}}_2{\mathrm{SO}}_4\to \mathrm{G}+\mathrm{R}+\mathrm{X} \\ (\mathrm{hot}\mathrm{conc}) \end{gathered}$$ are as follows:
2. $$\begin{gathered} \mathrm{Zn}+2{\mathrm{H}}_2{\mathrm{SO}}_4\to \mathrm{ZnSO}4+{\mathrm{SO}}_2+2{\mathrm{H}}_2\mathrm{O} \\ (\mathrm{hot}\mathrm{conc})\mathrm{G}\mathrm{R}\mathrm{X} \end{gathered}$$
3. The molecule R is ${\mathrm{SO}}_2$ and it is V-shaped molecule.
4. Hence statement A is correct.

B. $\mathrm{Z}$ is dirty white in colour

1. The unknown reactants in reaction $\mathrm{G}+{\mathrm{H}}_2\mathrm{S}+{\mathrm{NH}}_3\left(\mathrm{aq}\right)\to \mathrm{Z}+\mathrm{X}+\mathrm{Y}$ are as follows:
2. $$\begin{gathered} {\mathrm{ZnSO}}_4+{\mathrm{H}}_2\mathrm{S}+{\mathrm{NH}}_3\left(\mathrm{aq}\right)\to \mathrm{ZnS}+{\left({\mathrm{NH}}_4\right)}_2{\mathrm{SO}}_4+{\mathrm{H}}_2\mathrm{O} \\ \mathrm{G}\mathrm{Z}\mathrm{X}\mathrm{Y} \end{gathered}$$
3. The molecule Z is $\mathrm{ZnS}$ which is dirty white in color.
4. Hence statement B is correct.

C. Bond order of $\mathrm{Q}$ is $1$ in its ground state

1. the unknown reactants in reaction $$\begin{gathered} \mathrm{Zn}+\mathrm{NaOH}\to \mathrm{T}+\mathrm{Q} \\ \left(\mathrm{conc}\right) \end{gathered}$$ are as follows:
2. $$\begin{gathered} \mathrm{Zn}+2\mathrm{NaOH}\to {\mathrm{Na}}_2{\mathrm{ZnO}}_2+{\mathrm{H}}_2 \\ \left(\mathrm{conc}\right)\mathrm{T}\mathrm{Q} \end{gathered}$$
3. The molecule Q is ${\mathrm{H}}_2$ and bond order of ${\mathrm{H}}_2$ is $1$ in ground state.
4. Hence statement C is correct.

Explanation for incorrect option:

D. The oxidation state of $\mathrm{Zn}$ in $\mathrm{T}$ is $+1$

1. From the reaction: $$\begin{gathered} \mathrm{Zn}+2\mathrm{NaOH}\to {\mathrm{Na}}_2{\mathrm{ZnO}}_2+{\mathrm{H}}_2 \\ \left(\mathrm{conc}\right)\mathrm{T}\mathrm{Q} \end{gathered}$$ it can be observed that molecule T is ${\mathrm{Na}}_2{\mathrm{ZnO}}_2$.
2. The oxidation state of $\mathrm{Zn}$ in ${\mathrm{Na}}_2{\mathrm{ZnO}}_2$ is $+2$ and not $+1$ .
3. Therefore, statement D is incorrect.

Hence options A, B and C are correct,