Consider the following statements.
I.The transition metals and their compounds are known their catalytic activity.
II. They are able to adopt multiple oxidation states and to form complexes.
Choose the correct option.

Options

A. I is true
B. II is true
C. Both I and II are true
D. Neither I nor II is true

Answer

To analyze the given statements about transition metals, let's break down the question step by step.

### Step 1: Evaluate Statement I
**Statement I:** The transition metals and their compounds are known for their catalytic activity.

**Analysis:**
- Transition metals are indeed known for their catalytic properties. They can facilitate various chemical reactions without being consumed in the process.
- This catalytic activity is largely due to their ability to exist in multiple oxidation states, which allows them to participate in a variety of chemical reactions.
- Examples include the use of iron in the Haber process for ammonia synthesis and platinum in catalytic converters in vehicles.

### Step 2: Evaluate Statement II
**Statement II:** They are able to adopt multiple oxidation states and to form complexes.

**Analysis:**
- Transition metals are characterized by their ability to exhibit multiple oxidation states. This property is crucial for their role in catalysis and in forming various compounds.
- Additionally, transition metals can form complex ions with ligands (molecules or ions that can donate a pair of electrons to the metal). This ability to form complexes is a significant aspect of their chemistry, leading to a wide range of applications, including in biological systems (like hemoglobin) and industrial processes.

### Step 3: Conclusion
Both statements I and II are correct. Transition metals are known for their catalytic activity and their ability to adopt multiple oxidation states and form complexes.

### Final Answer
Both statements are correct.