The gas we use in the kitchen is called liquified petroleum gas (LPG). In the cylinder it exists as a liquid. When it comes out from the cylinder it becomes a gas (change-A) then it burns (change-B). The following statements pertain to these changes. Choose the correct one.

Options

A. Process A is a chemical change.
B. Process B is a chemical change.
C. Both process A and B are chemical changes.
D. None of these processes is a chemical change.

Answer

To solve the question regarding the changes that liquefied petroleum gas (LPG) undergoes when used in the kitchen, we need to analyze the two changes mentioned: Change A (when LPG becomes a gas) and Change B (when LPG burns). Here’s a step-by-step breakdown of the solution:

### Step 1: Identify Change A
- **Change A** refers to the process when LPG, which is stored as a liquid in a cylinder, comes out and transforms into a gas.
- This transformation from liquid to gas is known as **vaporization**.

### Step 2: Determine the Type of Change for Change A
- In Change A, LPG changes its state from liquid to gas but retains its chemical composition.
- Since no new substance is formed during this process, it is classified as a **physical change**.

### Step 3: Identify Change B
- **Change B** refers to the burning of LPG.
- When LPG burns, it reacts with oxygen in the air.

### Step 4: Determine the Type of Change for Change B
- During the burning of LPG, new substances are formed, including carbon dioxide (CO2), water vapor (H2O), and possibly carbon monoxide (CO).
- Since new substances are produced in this process, it is classified as a **chemical change**.

### Step 5: Evaluate the Statements
- Now, let’s evaluate the statements provided in the question:
1. **Process A is a chemical change** - This is **incorrect**; it is a physical change.
2. **Process B is a chemical change** - This is **correct**; it is indeed a chemical change.
3. **Both process A and B are chemical changes** - This is **incorrect**; only process B is a chemical change.
4. **None of these processes is a chemical change** - This is **incorrect**; process B is a chemical change.

### Conclusion
The correct statement is that **Process B is a chemical change**.

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