The most commonly used reducing agent is

Options

A. `AICI_(3)`
B. `PbCI_(2)`
C. `SnCI_(4)`
D. `SnCI_(2)`

Explanation

To solve the question regarding the most commonly used reducing agent, we can follow these steps:

### Step 1: Understand the Concept of Reducing Agents
A reducing agent is a substance that donates electrons in a chemical reaction and gets oxidized in the process. It reduces another substance by providing electrons.

**Hint:** Remember that reducing agents are oxidized themselves while reducing other substances.

### Step 2: Identify Common Reducing Agents
Common reducing agents include substances like hydrogen, carbon, metals like zinc, and metal halides such as tin(II) chloride (SnCl2).

**Hint:** Think about the elements and compounds that are known for their ability to donate electrons.

### Step 3: Analyze the Given Options
In the context of the question, we need to evaluate the options provided (not listed here). However, based on common knowledge, SnCl2 is a well-known reducing agent.

**Hint:** Look for compounds that are stable in a lower oxidation state and can easily be oxidized to a higher state.

### Step 4: Confirm the Properties of SnCl2
The chemical symbol for tin is Sn, and it can exist in oxidation states of +2 and +4. SnCl2 (tin(II) chloride) can easily be oxidized to SnCl4 (tin(IV) chloride), making it a good reducing agent.

**Hint:** Check the oxidation states of the compounds involved to understand the electron transfer process.

### Step 5: Write the Reaction
The oxidation of SnCl2 can be represented as follows:
\[ \text{SnCl}_2 + 2\text{Cl}^- \rightarrow \text{SnCl}_4 + 2e^- \]
This shows that SnCl2 donates electrons and gets oxidized to SnCl4.

**Hint:** Look for the balanced chemical reaction that illustrates the reducing action.

### Step 6: Conclusion
Based on the analysis, we conclude that SnCl2 is a commonly used reducing agent due to its ability to easily oxidize and reduce other substances.

**Final Answer:** The most commonly used reducing agent is SnCl2.