Question

Which of the following is/are example(s) of an exothermic reaction?

• A. Melting of ice
  
• B. Respiration
• C. Burning of a candle
• D. Evaporation of water

Answer 1

Answer: (B), (C)

The correct options are
B Respiration
C Burning of a candle

Endothermic reaction involves absorption of heat while exothermic reaction involves evolution of heat.

• Melting of ice- Energy is absorbed to break the chemical bond between the water molecules in order to convert ice into liquid water.
• Respiration- Energy is released during this process.
• Burning of candle- More energy is released during this process than the energy required to start the reaction.
• Evaporation of water- Energy is absorbed to break the chemical bond between the water molecules in order to convert water into water vapour.

Therefore, respiration and burning of a candle are examples of exothermic reaction whereas evaporation of water and melting of ice are examples of endothermic reaction.