Question

Write chemical equations for the reactions taking place when: (i) Manganese dioxide is heated with aluminium powder. (ii) Steam is passed over red hot iron.

Accepted Answer

(i) 3MnO2(s) + 4Al(s) -> 3Mn(l) + 2Al2O3(s) + Heat; (ii) 3Fe(s) + 4H2O(g) -> Fe3O4(s) + 4H2(g). (i) When $MnO_2$ is heated with $Al$ powder, a displacement thermite reaction occurs: $$3MnO_2(s) + 4Al(s) ightarrow 3Mn(l) + 2Al_2O_3(s) + 	ext{Heat}$$ (ii) When steam is passed over red-hot iron, magnetic iron oxide and hydrogen gas are formed: $$3Fe(s) + 4H_2O(g) ightarrow Fe_3O_4(s) + 4H_2(g)$$

Chemical Reactions of MnO2 and Iron

Explanation

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