Question

Select from the following a statement which is not true about the burning of magnesium ribbon in air:

• A. It burns with a dazzling white flame.
• B. A white powder is formed on burning.
• C. It is an endothermic reaction.
• D. It is an example of a combination reaction.
  {5pt}

Hint:

The burning of magnesium in air is a combination reaction (Mg + Osubscript{2} → MgO) and it releases heat, making it exothermic.

Answer 1

The Correct Option is C

Step 1: Magnesium Ribbon Combustion.
- Burning magnesium ribbon in air generates a bright white flame and magnesium oxide (MgO), a white powder. This is an exothermic process.
- The reaction of magnesium with oxygen is a combination reaction; two reactants yield a single product.
Step 2: Conclusion. Magnesium combustion is exothermic, not endothermic.
Consequently, statement (C) is invalid.