Which among the following substance is expected to have the highest ignition temperature? 

The correct answer is Coal.

Key Points

• Ignition temperature is the minimum temperature at which a substance catches fire and starts burning.
• Coal has a relatively high ignition temperature compared to substances like petrol, alcohol, or kerosene, making it less flammable under normal conditions.
• The ignition temperature of coal ranges from approximately 400°C to 700°C, depending on its type and composition.
• In contrast, substances like petrol and kerosene have much lower ignition temperatures, making them highly flammable.
• Higher ignition temperature materials like coal are often used in controlled combustion processes such as power generation in thermal plants.

Additional Information

• Ignition Temperature:
  • It is an important property for fire safety and industrial applications.
  • Substances with low ignition temperatures are more hazardous as they catch fire easily.
• Examples of Ignition Temperatures:
  • Petrol: ~247°C
  • Kerosene: ~220°C
  • Alcohol: ~363°C
  • Coal: ~400°C to 700°C
• Factors Affecting Ignition Temperature:
  • Moisture content in the material.
  • Type and composition of the substance (e.g., bituminous coal vs. anthracite coal).
  • Presence of oxygen and other external factors like pressure and humidity.
• Applications of High Ignition Temperature Substances:
  • Coal is widely used in industrial settings and thermal power plants due to its controlled combustibility.
  • High ignition temperature materials are preferred for long-term energy generation processes.