Question

Bauxite is an ore of :
A. Aluminium
B. Manganese
C. Copper
D. Iron

Answer 1

Hint: Bauxite is a sedimentary rock. Bauxite contains only 30%-45% alumina $\text{A}{{\text{l}}_{2}}{{\text{O}}_{3}}$, and rest, it has a mixture of silica, iron oxides and titanium dioxide and traces of zinc, phosphorous, nickel, vanadium and many more. Discuss the options one by one to find the answer by chemical formulas.

Complete step by step answer:
Let us discuss the ores of following options one-by-one:
A. Aluminium $\left( \text{Al} \right)$: The most important ore of aluminium is bauxite or Gibbsite $\left( \text{A}{{\text{l}}_{2}}{{\text{O}}_{3}}\text{.3}{{\text{H}}_{2}}\text{O} \right)$. Bauxite is a rock formed from laterite soil. It is found in tropical and subtropical regions. Bauxite is aluminium rich ore which is used for aluminium production and for production of chemicals or cements. The other ores of aluminium are cyanite $\left( {{\text{K}}_{2}}\text{O}\text{.A}{{\text{l}}_{2}}{{\text{O}}_{3}}\text{.4Si}{{\text{O}}_{2}} \right)$ and diaspore $\left( \text{A}{{\text{l}}_{2}}{{\text{O}}_{3}}\text{.}{{\text{H}}_{2}}\text{O} \right)$.
B. Manganese $\left( \text{Mn} \right)$: The important manganese ores are pyrolusite $\left( \text{Mn}{{\text{O}}_{2}} \right)$with manganese 63.2% in it, hausmannite $\left( \text{M}{{\text{n}}_{3}}{{\text{O}}_{4}} \right)$, rhodonite $\left( \text{MnSi}{{\text{O}}_{3}} \right)$ and manganite $\left( \text{M}{{\text{n}}_{2}}{{\text{O}}_{3}} \right)$. Ores containing manganese greater than 35 percent are commercially exploitable. Manganese ores containing iron oxides which in turn is used in steel-making.
C. Copper $\left( \text{Cu} \right)$: The important ores of copper are a yellow coloured chalcopyrite $\left( \text{CuFe}{{\text{S}}_{2}} \right)$ with 34% copper content, chalcocite $\left( \text{C}{{\text{u}}_{2}}\text{S} \right)$, a green coloured ore malachite $\left( \text{CuC}{{\text{O}}_{2}}.\text{Cu}{{\left( \text{OH} \right)}_{2}} \right)$ with 57% of copper content, a red coloured cuprite $\left( \text{C}{{\text{u}}_{2}}\text{O} \right)$ with 89% of copper content and a peacock ore bornite $\left( \text{C}{{\text{u}}_{2}}\text{Fe}{{\text{S}}_{4}} \right)$ with 63% of copper content.
D. Iron $\left( \text{Fe} \right)$: The important ores of iron are hematite $\left( \text{F}{{\text{e}}_{2}}{{\text{O}}_{3}} \right)$ with 70% iron content, magnetite $\left( \text{FeO}\text{.F}{{\text{e}}_{2}}{{\text{O}}_{3}} \right)$ with 72% iron content, magnesioferrite $\left( \text{MgO}\text{.F}{{\text{e}}_{2}}{{\text{O}}_{3}} \right)$ with 56% iron content, siderite $\left( \text{FeC}{{\text{O}}_{3}} \right)$ with 48.2% iron content and limonite $\left( \text{2F}{{\text{e}}_{2}}{{\text{O}}_{3}}.3{{\text{H}}_{2}}\text{O} \right)$ with 59.8% iron content.

Bauxite is an ore of Aluminium. The correct option is option ‘a’.


Note: Aluminium is produced from bauxite using Bayer’s method and Hall-Heroult process. Bauxite is a soft material, its colours are white, gray and reddish brown, earthy luster and has a low specific gravity. Bauxite is used in the aeroplanes making industry, electric industry and tool making industry.