`Tl^(3+)` acts an `"………….."` agent.

Answer

To determine the nature of the agent that \( \text{Tl}^{3+} \) acts as, we can follow these steps:

### Step 1: Understand the oxidation states of Thallium
Thallium (Tl) is located in Group 13 of the periodic table. It can exhibit multiple oxidation states, primarily +1 and +3. The +3 oxidation state is derived from the loss of three electrons.

**Hint:** Remember that elements can have multiple oxidation states, which can affect their chemical behavior.

### Step 2: Analyze the electronic configuration
The electronic configuration of Thallium is \( [Xe] 4f^{14} 5d^{10} 6s^{2} 6p^{1} \). From this configuration, we can see that Thallium can lose electrons to achieve different oxidation states.

**Hint:** Knowing the electronic configuration helps in understanding how many electrons can be lost or gained.

### Step 3: Identify the common oxidation states
In the case of Thallium, the +1 oxidation state is more stable due to the inert pair effect, where the s-electrons are less likely to participate in bonding. However, the +3 state can also exist.

**Hint:** The inert pair effect is crucial for understanding the stability of oxidation states in heavier p-block elements.

### Step 4: Determine the role of \( \text{Tl}^{3+} \)
When \( \text{Tl}^{3+} \) is present, it can accept electrons from other species, which indicates that it is capable of undergoing reduction. This means it can oxidize other substances.

**Hint:** An oxidizing agent is a species that gains electrons (is reduced) while causing another species to lose electrons (be oxidized).

### Step 5: Conclusion
Since \( \text{Tl}^{3+} \) can accept electrons and cause oxidation in other substances, it acts as an **oxidizing agent**.

**Final Answer:** \( \text{Tl}^{3+} \) acts as an **oxidizing agent**.

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