Which of the following involves both physical and chemical change?

Options

A. Burning of a candle
B. Rusting of iron
C. Cooking of food
D. Boiling of water

Explanation

To determine which of the following options involves both physical and chemical changes, we will analyze each option step by step.

### Step 1: Analyze the Burning of a Candle
- **Physical Change**: When a candle burns, the wax melts. This is a physical change because the wax changes its state from solid to liquid without altering its chemical composition.
- **Chemical Change**: The burning of the wick and wax produces new substances such as carbon dioxide and water vapor. This is a chemical change because the original substances (wax and wick) undergo a chemical reaction to form new substances.

**Conclusion**: The burning of a candle involves both physical (melting of wax) and chemical changes (burning of wax and wick).

### Step 2: Analyze Rusting of Iron
- **Chemical Change**: Rusting occurs when iron reacts with moisture and oxygen in the air to form iron oxide (rust). This is a chemical change because a new substance is formed, and the original iron cannot be recovered.

**Conclusion**: Rusting of iron involves only a chemical change.

### Step 3: Analyze Cooking of Food
- **Chemical Change**: Cooking food involves breaking down and rearranging the chemical structure of the ingredients, resulting in new substances. Once cooked, the original ingredients cannot be returned to their raw form.

**Conclusion**: Cooking of food involves only a chemical change.

### Step 4: Analyze Boiling of Water
- **Physical Change**: When water boils, it changes from a liquid to a gas (steam). This is a physical change because the chemical composition of water (H2O) remains the same.

**Conclusion**: Boiling of water involves only a physical change.

### Final Conclusion
Based on the analysis:
- The only option that involves both physical and chemical changes is the **Burning of a Candle**.