Question

Which among the following statements is true for $\text{Pt[(NH}_3)_2\text{Cl}_2]$?

• A. It is a neutral complex.
• B. In this complex chlorine atoms are in ionization sphere.
• C. The coordination number of Pt in this complex is 2.
• D. The oxidation state of Pt in this complex is +4.

Hint:

Any coordination compound that lacks ions written outside its square brackets is instantly a neutral complex because it does not dissociate into separate ionic units in solution!

Answer 1

The Correct Option is A

Step 1: Understanding the Question:
We must evaluate the physical and chemical properties of the coordination compound $\text{[Pt(NH}_3)_2\text{Cl}_2]$ to identify the single mathematically and structurally true statement among the choices.

Step 2: Detailed Explanation:
Let's analyze the properties of the given coordination complex system systematically:

• Coordination Sphere vs. Ionization Sphere: All components inside the square brackets [ ] form part of the inner coordination sphere. Because the chloride ($\text{Cl}^-$) ions are enclosed directly inside the brackets, they are bound directly to the metal center as ligands and are not present in the outer ionization sphere. This makes statement (B) false.

• Coordination Number: The platinum metal center is bound to two ammine ($\text{NH}_3$) ligands and two chloride ($\text{Cl}^-$) ligands. Since both are monodentate ligands, the net coordination number is $2 + 2 = 4$. This makes statement (C) false.

• Oxidation State: Let the oxidation state of Platinum be $x$. Ammine is a neutral ligand ($0$) and chloride carries a $-1$ charge. Since the total net charge on the complex is $0$: $$ x + 2(0) + 2(-1) = 0 \implies x = +2 $$ The oxidation state of Pt is $+2$, which makes statement (D) false.

• Net Complex Charge: Because there are no counter-ions balancing the brackets externally, and the internal charges cancel perfectly ($\text{Pt}^{2+}$ balances two $\text{Cl}^-$ ions), the compound carries zero overall net electrical charge. Thus, it is classified as a neutral complex, making statement (A) true.


Step 3: Final Answer:
The true statement is that it is a neutral complex, which corresponds to option (A).