Question

Select from the following a process in which a combination reaction is involved:

• A. Black and White photography
• B. Burning of coal
• C. Burning of methane
• D. Digestion of food

Answer 1

The Correct Option is B

In order to determine which option involves a combination reaction, we need to understand what a combination reaction is. A combination reaction is a type of chemical process where two or more substances combine to form a single product.

Option Analysis:

• Black and White photography typically involves the reduction of silver ions to metallic silver, not a combination reaction.
• Burning of coal: Coal is primarily composed of carbon (C). When coal burns, carbon reacts with oxygen (O₂) resulting in carbon dioxide (CO₂). This can be represented by the equation:

  C + O₂ → CO₂

  This process is a clear example of a combination reaction, where carbon and oxygen combine to form carbon dioxide.
• Burning of methane involves the reaction of methane (CH₄) with oxygen to produce carbon dioxide and water. The reaction is:

  CH₄ + 2O₂ → CO₂ + 2H₂O

  It is not a combination reaction; it is a combustion reaction.
• Digestion of food involves complex biochemical reactions, primarily decomposition (breaking down molecules), not a combination reaction.

Hence, the correct answer is Burning of coal, where a combination reaction is involved.