Which of the following compounds is used in anti - knock compositions to prevent the deposition of oxides of lead on spark plug, combustion chamber and exhaust pipe?

Options

A. Benzene
B. Glycol
C. 1, 2-Dibromoethane
D. Glycerol

Answer

To solve the question, we need to identify which compound is used in anti-knock compositions to prevent the deposition of lead oxides in engines. Here’s a step-by-step breakdown of the solution:

### Step 1: Understand the Context
Anti-knock agents are additives used in fuels to prevent knocking during combustion. Knocking can cause engine damage and is often associated with the presence of lead in gasoline.

**Hint:** Look for compounds that are known to be used in fuel additives or anti-knock formulations.

### Step 2: Identify the Compounds
The question provides several options (not listed here). We need to focus on the compounds that are commonly known to be used in anti-knock formulations.

**Hint:** Recall common anti-knock agents used historically in gasoline.

### Step 3: Research Common Anti-Knock Agents
Historically, tetraethyl lead was used as an anti-knock agent, but it led to the deposition of lead oxides in engine components. To mitigate this, other compounds were introduced.

**Hint:** Consider alternatives to lead-based compounds that prevent lead oxide deposition.

### Step 4: Identify 1,2-Dibromoethane
1,2-Dibromoethane is known to be used in anti-knock compositions. It helps to prevent the deposition of lead oxides on engine parts like spark plugs and combustion chambers.

**Hint:** Look for information on 1,2-Dibromoethane and its applications in automotive fuel.

### Step 5: Confirm the Answer
Based on the information gathered, we can conclude that 1,2-Dibromoethane is indeed the compound used to prevent the deposition of lead oxides in the engine.

**Final Answer:** The compound used in anti-knock compositions to prevent the deposition of oxides of lead is **1,2-Dibromoethane** (option number 3).

### Summary of Steps:
1. Understand the role of anti-knock agents.
2. Identify the compounds listed in the options.
3. Research common anti-knock agents.
4. Identify the specific role of 1,2-Dibromoethane.
5. Confirm that 1,2-Dibromoethane is the correct answer.