The determination of heat of combustion is carried out with

Step 1: Analyze the question The question asks which apparatus is used to determine the heat of combustion, which is the heat released when a substance burns completely in oxygen.

Step 2: Explain the concept Heat of combustion is measured in a bomb calorimeter. This is a strong, sealed steel container (the "bomb") that holds the sample in excess oxygen under high pressure. It sits inside a known mass of water. The sample is ignited electrically, and the heat released raises the temperature of the surrounding water.

The heat released is calculated with:

Heat = (mass of water × specific heat capacity of water × temperature rise) + (heat capacity of the calorimeter × temperature rise)

Dividing this by the number of moles of the substance burned gives the molar heat of combustion.

Step 3: Check each option

• A. A thermometer: It only measures temperature change. It is a part of the setup, but it cannot determine heat of combustion on its own.
• B. A bomb calorimeter: It is designed for burning a sample completely and measuring the heat released. ✔
• C. An evaporating dish: It is used to evaporate solutions to get crystals. It is not used to measure heat.
• D. A boiling tube: It is used for heating small amounts of substances. It is not used to measure heat of combustion.

Step 4: Answer The correct option is B, a bomb calorimeter.

Tip: Link the words "combustion" and "bomb". Combustion is an explosive-type burning, so you need a "bomb" to contain it. For heats of solution or neutralization, a simple calorimeter (like a plastic cup with a thermometer) is enough.