Question

The correct statements among the following are.

A. Basic vanadium oxide is used in the manufacture of $H_2SO_4$.
B. The spin-only magnetic moment value of the transition metal halide employed in Ziegler-Natta polymerization is 2.84 BM.
C. The p-block metal compound employed in Ziegler-Natta polymerization has the metal in +3 oxidation state.
D. The number of electrons present in the outer most 'd' orbital of metal halide employed in Wacker process is 8.

Choose the correct answer from the options given below:

• A. A and B Only
• B. A, C and D Only
• C. C and D Only
• D. B, C and D Only

Hint:

Identify the catalysts: $V_2O_5$ (amphoteric) for $H_2SO_4$; $TiCl_4/AlEt_3$ for Ziegler-Natta; $PdCl_2$ ($Pd^{2+}$ is $d^8$) for Wacker process.

Answer 1

The Correct Option is C

To solve this, we evaluate each technical statement based on industrial chemistry and coordination chemistry principles:

1. Statement A: In the Contact process for the manufacture of Sulfuric acid ($H_2SO_4$), the catalyst used to oxidize $SO_2$ to $SO_3$ is Vanadium pentoxide ($V_2O_5$). In $V_2O_5$, Vanadium is in its maximum oxidation state of $+5$. High oxidation state oxides of transition metals are generally acidic or amphoteric, not basic. Specifically, $V_2O_5$ is amphoteric but predominantly acidic in nature. Thus, statement A is incorrect.

2. Statement B: Ziegler-Natta polymerization uses a catalyst system typically consisting of $TiCl_4$ (a transition metal halide) and $Al(C_2H_5)_3$. In $TiCl_4$, Titanium is in the $+4$ oxidation state. Titanium ($Z=22$) has a ground state configuration of $[Ar] 3d^2 4s^2$. $Ti^{4+}$ has the configuration $[Ar] 3d^0 4s^0$, meaning it has zero unpaired electrons. The spin-only magnetic moment formula is:

$$\mu = \sqrt{n(n+2)}\text{ BM}$$

where $n$ is the number of unpaired electrons. For $n=0$, $\mu = 0\text{ BM}$. Even if $TiCl_3$ ($Ti^{3+}$, $3d^1$) were used, $\mu$ would be $\sqrt{1(3)} = 1.73\text{ BM}$. A value of $2.84\text{ BM}$ corresponds to $n=2$ unpaired electrons. Thus, statement B is incorrect.

3. Statement C: The p-block metal compound used in Ziegler-Natta catalysts is Triethylaluminium, $Al(C_2H_5)_3$. Aluminium (Al) is a p-block element located in Group 13. In $Al(C_2H_5)_3$, Aluminium is bonded to three ethyl groups, resulting in a $+3$ oxidation state. This matches the statement. Thus, statement C is correct.

4. Statement D: The Wacker process converts ethene to acetaldehyde using a catalyst system of $PdCl_2$ and $CuCl_2$. The primary transition metal halide is $PdCl_2$. Palladium ($Z=46$) has a ground state electronic configuration of $[Kr] 4d^{10} 5s^0$. In $PdCl_2$, the oxidation state of Palladium is $+2$. The configuration of $Pd^{2+}$ is $[Kr] 4d^8$. Therefore, there are exactly 8 electrons in the outermost 'd' orbital. Thus, statement D is correct.

Comparing our findings with the options, only C and D are true. Hence, the correct answer is option 3.