The correct option is (c) 2 and 3 only.
Explanation
The burning of a magnesium ribbon in air is a fundamental example of a chemical reaction, specifically a combination reaction, where a metal reacts with oxygen to undergo a permanent chemical change.- Statement 1 is Incorrect: Magnesium is a reactive metal that burns with a characteristic dazzling white flame (intense white light), not a dull blue flame. This intense light is bright enough to be temporarily blinding, requiring eye protection during the experiment.
- Statement 2 is Correct: The process is a chemical change, meaning the product formed is chemically distinct from the reactants. The original substance is magnesium metal (shiny, flexible), while the resulting ash is a white, powdery ionic compound with different physical and chemical properties.
- Statement 3 is Correct: The reaction involves the combination of magnesium ($Mg$) with oxygen ($O_2$) present in the air to form a new substance called magnesium oxide ($MgO$). The chemical equation for this reaction is:
$2Mg(s) + O_2(g) \rightarrow 2MgO(s)$
Key Takeaway: The burning of magnesium is an irreversible chemical change characterized by a dazzling white flame and the formation of white magnesium oxide powder.