Y is formed when X is heated in absence of air. Y is tough, porous and black substance. Both X and Y are carbon-rich materials. What could X and Y be?

Options

A. X = Coal, Y = Coke
B. X = Petroleum, Y = Petrol
C. X = Coal, Y = Coal tar
D. X = Petroleum, Y = Diesel

Explanation

To solve the question, we need to identify the substances X and Y based on the given clues. Let's break down the information step by step.

### Step 1: Analyze the clues
- **Clue 1:** Y is formed when X is heated in the absence of air.
- **Clue 2:** Y is described as a tough, porous, and black substance.
- **Clue 3:** Both X and Y are carbon-rich materials.

### Step 2: Identify X
Since Y is formed from X when heated in the absence of air, we can deduce that X is likely a carbon-rich material that undergoes a transformation. A common carbon-rich material that can be heated to produce another substance is coal.

### Step 3: Identify Y
When coal (X) is heated in the absence of air, it undergoes a process known as destructive distillation. This process results in the formation of coke (Y), which is known to be tough, porous, and black.

### Conclusion
Based on the analysis:
- **X is coal.**
- **Y is coke.**

### Final Answer
X is coal, and Y is coke.

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