Which of the following has highest calorific value ?

Options

A. Kerosene
B. Biogas
C. Butane
D. Ethanol

Answer

To determine which of the given substances has the highest calorific value, we will compare the calorific values of each substance provided in the question.

### Step-by-Step Solution:

1. **Understanding Calorific Value**:
- Calorific value is defined as the amount of heat energy produced when a substance is completely burned. It can be expressed per mole, per unit mass, or per unit volume.
- Higher calorific values indicate that a substance releases more energy when burned.

2. **List the Given Substances and Their Calorific Values**:
- Kerosene: 46-51 MJ/kg
- Biogas: 20 MJ/kg
- Butane: 49.1 MJ/kg
- Ethanol: 29.7 to 29.9 MJ/kg

3. **Identify the Highest Calorific Value**:
- From the values listed:
- Kerosene: Average of 46-51 MJ/kg (let's take 51 MJ/kg for comparison)
- Biogas: 20 MJ/kg
- Butane: 49.1 MJ/kg
- Ethanol: Average of 29.7 to 29.9 MJ/kg (let's take 29.9 MJ/kg for comparison)
- Now, we compare these values:
- Kerosene: 51 MJ/kg
- Biogas: 20 MJ/kg
- Butane: 49.1 MJ/kg
- Ethanol: 29.9 MJ/kg

4. **Comparison**:
- Kerosene (51 MJ/kg) > Butane (49.1 MJ/kg) > Ethanol (29.9 MJ/kg) > Biogas (20 MJ/kg)

5. **Conclusion**:
- The substance with the highest calorific value among the options provided is **Kerosene** with a calorific value of 51 MJ/kg.

### Final Answer:
Kerosene has the highest calorific value among the given options.