Manganese is extracted by heating manganese dioxide with aluminum powder. Which one of the following statements with regard to the reaction is correct?

The extraction of manganese by heating manganese dioxide (MnO2) with aluminum powder is a classic example of an aluminothermic or thermite reaction. These displacement reactions are highly exothermic, meaning they release a significant amount of heat [3]. In such processes, a more reactive metal like aluminum acts as a reducing agent to reduce the metal oxide [3]. The heat evolved is so intense (often exceeding 2000 °C) that the resulting metals, such as manganese or iron, are typically produced in a molten (liquid) state rather than solid [4]. According to the reactivity series, aluminum is more reactive than manganese, allowing it to displace manganese from its oxide [3]. Therefore, statement 1 is correct as the reaction is inherently exothermic, while statements 2, 3, and 4 are scientifically inaccurate in the context of this specific chemical process.

Sources

1. [1] Science , class X (NCERT 2025 ed.) > Chapter 3: Metals and Non-metals > 3MnO2 (s) + 4Al(s) → 3Mn(l) + 2Al2O3 (s) + Heat > p. 52
2. [3] Science , class X (NCERT 2025 ed.) > Chapter 1: Chemical Reactions and Equations > What you have learnt > p. 14
3. [4] https://www.sciencedirect.com/science/article/abs/pii/S073519332300502X